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The easy-on, easy-off SmartWool Men's PhD HyFi Full-Zip Top is the easy option when winter blows in the first cold front of the season. The merino wool-nylon bi-component jacket holds in heat and addresses your sweat as you slice through gusts of chilly air, so you can keep on trucking all day long. The HyFi fabric's nylon outer face rebuffs chilly winds and resists abrasion, while the soft, breathble merino wool knit on the interior moves sweat vapor away from your skin, making this jacket well-suited for high-output aerobic activities like running or cycling. As a bonus, wool's natural antimicrobial properties keep it fresher than any all-synthetic gear in your athletic wardrobe. And engineered thumbhole cuffs provide just enough protection when the cold's making it hard to get going on an early-morning outing.

  • PhD HyFi (64% merino wool, 36% nylon)
  • Wind and abrasion resistant and thermoregulating
  • Articulated elbows
  • Center front zipper, full draft flat, zipper garage
  • Thumbhole cuffs
  • Two hand, one chest zip pocket
  • Reviews
  • Q & A

What do you think about this product?

Have questions about this product?

Great for layering

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

This is my number one layering piece. It easily slips over a long sleeved smartwool baselayer shirt without pulling the sleeves up and it has a close fit that is perfect wit a trim fit Arcteryx jacket.

I would not recommend it combined with a funnel zip top or similar as this probably will make it a little to tight around the neck when zipped up. But with a crew it is just perfect when I zip all the way up.

I only wish it could have been a bit lighter.

The thumb loops are, well they are thumb loops. more important is that the sleeves are long enough so that they can be used. I have experienced that they stretch just enough to make it comfortable and not give the feeling of someone trying to cut my thumbs off at the base.

Had to return one because of some issues with the zipper but my other one (couldn't do with just one) is 100% ok and zips easily up and down.

Ordering a replacement as I speak (or should I go for two? hmmmm....)

I see that the layer is 'wind resistant'...

I see that the layer is 'wind resistant' but I am not too sure what that means. I am looking for a jacket to run or walk on the beach in 50-60 degree temp and 20mph wind. Would I require an additonal wind break to wear with this piece to be comfortable?

J Wool,

Your question is somewhat of a personal decision and depends quite a bit on your personal comfort preferences. The SmartWool PhD HyFi Full-Zip Top is "wind resistant" which means it will significantly reduce the winds ability to chill you, but you will still feel it somewhat at high enough speeds.

The real difference maker is not the wind speed but rather the temps that the wind is coming at you with. For the temps and winds you describe I would feel very comfortable running in this top without any additional top layer. However, if the temps became much colder (e.g. 30-40 degrees) I would recommend layering a light running jacket over the top for additional protection.