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Welcome to the Smartwool PhD Running Light Micro Sock. The micro cuff provides minimal coverage while you tear down the mountain trail, ReliaWool technology pads the heel and forefoot to boost shock-absorption and durability, and non-itchy merino wool breathes well and helps prevent odors from accumulating.

  • Blended composition maximizes the benefits of each separate material while minimizing fabric drawbacks
  • Non-itchy merino wool breathes well, helps regulate body temperature, and is naturally odor resistant
  • Nylon components dry quickly, breathe well, and add extra durability
  • 4Degree Elite Fit system employs ankle, instep, and arch elastic bands for better stretch, fit, support, and circulation
  • ReliaWool tech on the bottom of the sock combines high-density impact zones along the ball and heel provides long-lasting protection
  • Virtually seamless toe construction limits irritation and chaffing
  • Reviews
  • Q & A

What do you think about this product?

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Great sock for warmer winter days

  • Familiarity:I've used it several times
  • Fit:True to size

This is a great sock for warmer winter days. When the wind chill isn't felt all the way to your bones. Fits really well in my boots. The boots I use only have enough space for a thin-ish sock, otherwise this sock is not meant for boots with a ton of extra space.

Not Stoked.

I've worn these maybe 2-3 times. On the third wear (all day in Maple Cayon, UT) I took the socks off and noticed two holes.

No rocks in my shoes. And I haven't walked around with just the socks on and no shoes. The socks have always been worn with shoes on the outside when walking around.

Pretty disappointed in the lack of quality.

Not Stoked.

Hey Ben,

I've heard the same things from other folks that have this pair. Everyone has done nothing but raved about the quality.

It's possible I either got the one defective pair or that I just managed to break it faster. I have an ability to break things like no other.

Great to hear that others are not experiencing this!

These socks feel great!

  • Familiarity:I've used it several times
  • Fit:True to size

These socks feel great! Perfect for running, hiking, or everyday use. I never thought socks could offer "support" but the compression design really helps. These offer much more support than the old cotton socks I have been wearing for years. I would definitely purchase these again.

Light, Dry, and Warm

  • Familiarity:I've used it several times
  • Fit:True to size

I can't tell you any more about the technical specs on these socks than you see above. But obviously someone put a serious amount of thought into the blend of the Merino, and the way these socks are contructed (putting high-durability blends in traditional high-wear areas). They are a good mid weight sock that keeps my feet warm and dry even on long runs in icy conditions.

Socks are the silent servants in my gear closet. I want them to work so well that I forget they exist, and the SmartWool PhD Running Light Micro Sock does this better than the rest.

I dig it, you'll dig it. Trust me.

  • Familiarity:I've put it through the wringer
  • Fit:True to size

I wear it day in and day out. The "Light" has the right amount of cushion for me. I found that with anything less than that, the "Ultra Light" socks, I wore out the front of the sock before I could really put them to use. Nothing sucks more than your toes poking through the front of your sock. Maybe sand in your underwear.

Awesome Socks

  • Familiarity:I've put it through the wringer
  • Fit:True to size

I've ran in these socks almost exclusively for a year. I only have one pair of them... They're very durable and never get stinky. They give just a bit of cushion, but are not too thick by any means.

Big SmartWool fan, but prefer Ulta Light

  • Familiarity:I've put it through the wringer
  • Fit:True to size

Much of what I wear for mountain biking, trail running, skiing, working out is SmartWool. These socks, however, are ok as I prefer the Ultra Light (they are much thinner). Otherwise, the socks seem to have a similar fit to the Ultra Lights. In the end, I think it is just a matter of preference - thick/thin socks.

Once you Smartwool, you never go back

    Got my first pair of Smartwools 5 years ago and have never gone back to regular socks since. The 'running light micro' is my favorite design. It's no-show and the lip on the heel prevents chafing. The 'light' weight seems to last a few months longer than the 'ultra light' weight socks - I get at least 1-2 years out of mine. I'd recommend the ultra light socks for minimalist running shoes or cycling, though. These are great for everything else - casual, hiking, running, etc! Wonderful product. Fill your sock drawer with 'em!

    Extremely comfortable and moisture wicking.

      If you are used to the typical cotton or thin ASIC's running socks you will be in for a surprise. I ran cross country for over a year using typical cotton socks and then for another 4 years with the nice $15.00 Asic's thin runners socks. The primary problem I had was moisture build up and comfort. Then the asids took take of the moisture part and were a bit more comfy. The only problem I have from the asics was the odor control. Then I finally gave smart wool a try. As soon I I slipped them on I felt a tremendous difference and they took off from there. Excellent breathability, excellent warmth or cooling abilities, and no odor even when I whore them for 5 consecutive days running.

      Bought for hiking trip

      • Familiarity:I've used it once or twice and have initial impressions

      I hiked 18 miles (in Chicago) as a trial for a planned hiking trip in New Zealand (Milford Trek) which spans 33 miles over 5 days. I felt very comfortable with these socks; you will want a sock liner to use with these type of wool socks, planning to use these with Salomon XA Pro 3D Ultra GTX shoes and the longer cousins of these type of smartwool socks with North Face Dhaulagiri II GTX which I simply love and wish they were still on the market!