This shirt has kept my girlfriend and made her my wife. Comfy, warm and it never smells, 21 days of touring in the same shirt and you could wear it to the bar and no one would notice. Does not breathe as well as plastic, but is better on every other front.

Another home run from Arc'teryx. I bought this piece because of persistent problems with Under Armor 2.0 layers, namely, non-stop itchiness and being too quick to give off odor after and while wearing. The RHO is fantastic, super light and compressible for packing and has a great warmth:weight ratio. Having the zip neck allows easy venting and the fit is superb. I layer it under softshells and pull overs like the Apache AR Zip, and it works GREAT under body armor for all of us doing serious social work. There's no chafing, even with other gear and kit like back-up weapons placed close to it under a uniform. While it might look like the chest placement for the pocket would create issues with armor, I've not had that problem at all as it sits very close and flush to other surfaces. The wool is very comfortable, doesn't itch, wicks well and quickly, and doesn't hold onto smells. Having FR qualities as it does, it's also a safer alternative to synthetics. Just make sure the fit is close and appropriately snug.

All in all, I give this my highest recommendation. No more synthetic for me, and I'm already looking at getting the bottoms...

I am gonna bail on all the synthetics from here on out. Good-bye Patagonia Capilene... Good-bye Under Armour Cold Gear... Hello Lamb Chops I am here to stay! Absolutely the best base layer I have ever owned. I don't care about the special washing requirements. The itch wasn't even noticeable and I have sensitive skin. I was amazed at how little body odored was trapped by this material. As with most things now-a-days, you pay for performance when it comes to winter gear. Arc'teryx never ceases to amaze me. I am buying the matching bottoms.

rather than stuffing a week's worth of long underwear in your bags in the hopes that you don't smell like a sweaty turd on the ski hill or a backcountry trip, pick up one of these. my girlfriend still gives me warm hugs after wearing this top for four days straight, which is about 4 days longer than usual with a synthetic top. it's warm, lightweight, and best of all YOU DON'T STINK!!

I am 6'3", 180 lbs and own a LARGE. It is a SICK baselayer, and fits tight but not overly tight. Wicks away sweat like I have never experienced before with synthetics. WOOL is the way to go. Not itchy against my skin at all. I can fit a t-shirt under it when desired and wear it over that, or even alone as a form-fitting sweater. I used the pocket to hold my cellphone while skiing to keep it next to my body and keep the cold from draining my battery. Worked great. Could also place valuables like I.D. or even a key in the pocket to keep them safe & secure.The zip is NOt annoying at all to me, and never do I get a zipper chill from a cold zipper. Used it many times without washing it and it still doesnt stink. THE ULTIMATE BASE LAYER. Do not hesitate to buy one, especially if you currently own a synthetic layer like Under Armour- you wont be dissapointed you spent $120 on the RHO LTW!

This shirt is pretty good. In the hierarchy of shirtdom, for hard core hikers, i place the patagonia capilene stuff at the top, then the smartwool stuff, and then this. they are all nice! but capilene breaths so much better than this or the smartwool woolies. the woolies are better for really keeping you warm in the absence of lots of exertion. and heroically fend of sweat stench much better than the capilene stuff. however, i've found that a thin silk base layer teamed with a capilene 3 matches the wools, in the heat regard, and far exceeds the breathability.

i prefer the smartwool shirts over this, by a slight margin. the smartwool shirts have a less technical look, and, since i don't use wools much for strenuous hiking, i might as well have a wool shirt that looks less nerdo.

this shirt has a pretty trim fit. i got a medium, and it is nice and skin hugging, but not muscle mapping. it has decent arm length, though not as good as my arcteryx gamma mx jacket, in this regard. i have longish arms (6'5") and the medium just barely meets the arm length criteria, for me. note that the Rho LT model is much different in this regard. the Rho LT medium is far too small for me, but the LTW fits pretty well.

I am very impressed with my new base layer. It keeps it's shape with wear and the colors are even better than on the screen. I am thinking of getting another.

Awesome. Definitely keeps you warm on the slopes or while climbing on a cold day. The Rho is just as everyone says, you can wear it for days and not smell. I think I am giving it for a gift this holiday to a friend of mine who constantly stinks. The Rho will stomp out the smells.

Beware: the Rho runs slightly small. I normally wear a medium in everything. I should have gotten a large.

Awesome. Definitely keeps you warm on the slopes or while climbing on a cold day. The Rho is just as everyone says, you can wear it for days and not smell. I think I am giving it for a gift this holiday to a friend of mine who constantly stinks. The Rho will stomp out the smells.

Beware: the Rho runs slightly small. I normally wear a medium in everything. I should have gotten a large.

...yes, I bought another. And now I'm back looking at a third. Great baselayer!!

10 days ago I wore the Rho LTW as my only top on a cayoneering trip through Pine Creek in Zion National Park while others wore wet suits. Temps ranged from 75F down to 45F and at times I was completely submerged in stagnant pools. The Rho LTW kept me warm (enough), dried quickly, and didn't stink from sweat or bacteria. I'm buying another!

Wear often, stay out long. One of my most versatile layering options. Paired with the LTW boot length bottoms, perfect in the winter. Over a t-shirt, it cuts the fall chill as the sun sets on the Spearhead concert.

Great product, however, little odd sizing, long arms but far from it is a great product. To bad it is made in China. I have the Stinger pants and the jacket and they are made in Canada = GOOD quality, the chines are far off when it comes to quality, that's why TNF is not as good any longer.......and I know I have jackets and pants from the good old times, = made in USA and they are still good.
I have the Icebreaker Tech-Top 260 to compare with The Arcteryx Zip top....The Iceabreaker is great too, but the arms too short, the neck is very high and that is good, but one can get a feeling of someone is strangle you, the body could be little longer, the Arcteryx has long arms and the body is long too but the neck slightly too short.....with a longer neck and the Arcteryx will be optimal.
No smell, well I am not sure if you guys are sitting in front of the fire! I am out skiing, biking in sub zero temperatures in Sweden and both sweaters keeps me warm but I also sweet a lot and a wet merino wool sweater smells like a wet dog, but no smell when it is dry again.

I've used the Rho LT and LTW - and the LTW is a huge upgrade. Never stinks, always warm (I put in 10 miles XC skiing in 20 below with this and a Monkeyman), and stretches enough to fit well even over lighter baselayers.

This garment is great. Comfortable, not itchy, nice color, fully - i mean fully- functional item. It is tight fitting, keep it in mind when buying your size. It's NOT worth every penny like everyone says, because it;s super expensive but yeah that's what it costs.

i use this bad boy for everything in the colder months. It's awesome for my trail runs, although I wish the orange was brighter to keep the hunters from thinking I'm game. The wool isn't as soft as my socks but feels more durable. Smells like a wet dog after I use it but way better than that stank BO you get from other fabrics. Got an awesome fit for my lean body and the pocket is great for a car key or handwarmers.

This is the best merino wool 1/4 zip I have ever seen. It feels heavy duty and warm but it's lightweight. I haven't had a chance to try it in cool weather yet but it has my full confidence and it will be the first base layer I go to. I am 5' 11" about 155# and a medium is perfect. It is a little long but personally I like that a lot more then being a little short.

This is a great Merino wool product. The fit is super nice and its warm on cold days (bummer :-). I was a little sceptic about the zip, since zips often can irritate more than please, but this zip has been really well designed. When ziped all up it dont feel bulky or strange. And like everyone else is saying, it really does a good job keeping the stank from sweat away for a looong time. Spensive, but worth it.

Warm and comfortable. Not only functional, but also looks good. I have worn it casually with jeans and also skiing yesterday in Austria. I am converted to wool!

I bought this shirt in late October and it has been my "go to" shirt for this winter. I have used it as my warmth layer for all my cold weather activities - hiking, running, skiing, soccer, a round of golf - and general wear around the house. The shirt has lived up to all the claims of keeping you warm while completely resisting odor.

For my build (6'1", 185) I would typically by size Medium. But after reading previous reviewers' comments about the fit, I went with the Large. It is fitted but is not tight and leaves me enough room to wear a compression shirt underneath. The length is fine for my height and would be fine for anyone a few inches taller.

- A note on the color : although the COFFEE BEAN color looks brown in the images, it is definitely a true OLIVE color.

- I also purchased both the Delta LT Pullover and Covert Vest in Medium which I have occasionally layered comfortably over the large RHO LTW.

This is, by far, the best base layer I've ever owned. This shirt has covered my stinky existence for three years of hard riding and skiing. I'm 6'3 245 and run extremely hot... god knows how many liters of sweat have passed through this shirt, yet I can still wear it 5 days in a row without a wash and it does not smell a bit. Warm: Check. Comfortable: Check. Stink Proof: Check.

The only downside is the price. Get over it because this thing will last you long enough to make up for the three other base layers you would have bought and torn through otherwise.

Icebreaker vs. the Arc base layer - being as large as I am my vote goes to Arc's products; they are a little more generous.

I spend alot of time outside either for work or backpacking and I used to be a die hard UA fan when it came to my base layer. That was until I tried the Arc'Teryx Rho LTW. I actually shut the heat in my basement and put the top and bottoms. In less than two minutes I was toasty. I even went outside in sub 40 degree temp and was still warm although there wasn't any wind. I'm Sold!! All I have to do now is get a few more tops so that I don't look like I own only one shirt.

Bought three of these tops as well as the bottoms (leggings) also in the same Merino wool material; beats man made stuff any day. Thin but very warm and makes layering clothes and therefore temperature control easy. Small pockets useful for keeping AA/AAA batteries operational in sub zero temps which I had to do recently during a trip to Colorado. You also finish the day's climbing in material that doesn't smell. Quality clothes. Worth the cost. Highly recommended.

This was my first Arc'teryx purchase. Very happy with the quality, found the fit to be a little small (had to return the M for a L). Very high quality wool, breathes very well, never smells.

A very comfortable wool layer that slides right over a Rho ls crew baselayer. Good length, easy to ventilate, comfortable around your neck, no stink. Always in my pack. Should be in yours.

A very comfortable wool layer that slides right over a Rho ls crew baselayer. Good length, easy to ventilate, comfortable around your neck, no stink. Always in my pack. Should be in yours.

Add me to the believers. I love my capilenes but the Rho zip top is much better. It's warmer, stretchier and keeps the ripeness away for days and days. I wore it right out of the box for a week before washing. It didn't have as much as a faint body-odor smell but I somehow felt guilty for not washing it for so long, heh. Anyway, you'll only need to bring one of these on that week-long trip, freeing up pack space and reducing weight. It's worth it.

Like many others have said, it looks great, fits great, and doesn't stink after a long day (or several) of skiing. But like all things Arc'teryx, you are paying a premium to have that little bird fossil logo on your chest.

Bottom line - You will be happy with this top but you can buy just about the same thing from Smartwool or the Backcountry brand for a bit cheaper.

6'3" bought a large and overall fits real nice, very snug throughout the body as it should be. Could be a tad longer.

Really like it and use it as base and second layer. great fit, very stretchy, long arms and torso, true to size but a little bigger than other brands (icebreaker). I really value the extra length though. the only thing i could consider a drawback is that it's a bit heavy. that makes me wonder if it's a bit tightly woven, and consequently retain more moisture. because of that I almost never use this shirt when i anticipate a lot of sweating (spring ski touring e.g.). i use a thinner wool shirt for that. but the times it has been used i feel like it deals pretty well with moisture. top notch quality! For resort skiing it has been great though, both as base and second.

This shirt is great. Uber comfy and soft, it almost feels like a brushed cotton, but stretchier, warmer, and "higher performance". I went running with it after sunset when it was about 40 to 45 outside and had no temperature complaints, despite the light rain! My only complaint is that, the sleeves are a tad long. I'm a lean 5' 8" 170 and everything about this shirt fits great as a base-layer except the sleeve length, and even that could be fixed by adding monkey thumbs. I might even just get some sewn in! Otherwise I love it, I just need more uses for it!

Breathes great and keeps me toasty. I like it.

bought for a guy friend of mine and he totally loves it. used it skiing in Breck. and kept him warm. also, looks good on! :)

Extremely functional either as just a top or as a layer. The wicking properties are exceptional to keep you warm and dry. I wear it quite often.

The top is what you expect from Arcteryx, quality and workmanship. However he use of wool cause a few problems for me. It was a little itchy and washing it was a pain. I had to do a seperate load with "wool" friendly detergent. The description on item should have mentioned that. I hate high maintenance and not being able to just throw the top in with my other camping gear just sucks.

This is one of the best fitting layers you can get. Even after wearing it for multiple days it retains it shape. The neck portion also stays snug. It's as good or better that Icebreaker and Ibex merino products. I wore this today under a Marmot wind shirt for a cold (upper 20Fs low 30Fs) mountain bike ride and it was just the right comb. Great product as usual from Arc'teryx. Of course this site always has the best choice of products and excellent service.

This is another great item from Arc’teryx. Not uncommon with Arc’teryx, this item is very expensive but the product is worth it if you are out using it all the time. This is a great shirt as a base layer thus it is very close fitting, so do not expect to get any layer underneath it. Although it has a very contoured fit it dose not feel restrictive at all. Some people complain that the Merino wool is still a little itchy for them, however I have not found this to be a problem. I have worn this shirt mile after mile running, snowshoeing and camping and it dose not get stinky like Capilene. Overall this is a great product and has replaced almost all of my other Capilene base layer shirts as I don't get around to wearing them now, only when this one is in the wash. A little expensive, but worth it.

Very nice base layer that does not stretch out over time.
However the merino wool was itchy, so I could not wear it. However I think this itchiness is only perceived by a small few, so for those that need a wool layer, this is great.
Compared to my synthetic base layer, this wool layer did not feel as clammy... I would love to wear this as my base layer if it were not my sensitivity to the itchiness.

Excellent lightweight layer, comfortable next to skin, perfect for early fall, milder temps.

This is a soft and warm shirt for your outdoor adventures or wearing around town or at home! It is stylish, smells good, and I love the 4-way stretch! I usually wear it under my jacket while snowboarding.

You can't beat the temperature regulation of wool. It keeps you warm when you need it, but doesn't bake you when the weather is a little more mild. If you don't like snug, form-fitting garments, this is probably not the top for you. I usually don't care too much for the form fit, but this thing is so stretchy, that it's still pretty comfy. If you're looking for a no-bulk, excellent temperature regulator - this is the top for you.