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SmartWool PhD Cycling Ultra Light Micro Sock

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Item # SWL0564

 This model is no longer in stock.

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Item # SWL0564


Treat your feet sweet to beat the heat.

You'll wonder how Smartwool managed to squeeze this much intelligent technology into a package so small that doesn't require recharging. The PhD Cycling Ultra Light Micro Socks keep your feet dry and comfortable all summer without ridiculous floodwater tan-lines.

  • 4-Degree fit system to provide a secure, comfortable fit around the heel, arch, and instep
  • Wool-on-wool system adds an extra layer of wool to the heel and toe areas for shock-absorption and durability
  • Made with odor-reducing New Zealand Zque Merino wool

Tech Specs

63% merino wool, 35% nylon, 2% elastic
below the ankle
Recommended Use:
Manufacturer Warranty:

Size chart


Socks (Shoe Size Reference)

Sock Size →
Small Medium Large X-Large
US MEN'S 3 - 5.5 6 - 8.5 9 - 11.5 12 - 14.5
US WOMEN'S 4 - 6.5 7 - 9.5 10 - 12.5 N/A
EU 34 - 37 38 - 41 42 - 45 46 - 49
UK 2 - 4.5 5 - 7.5 8 - 10.5 11 - 13.5

Sock Size →
X-Small Small Medium Large
US 6 - 8.5 9 - 11.5 12 - 2.5 3 - 6
EU 22 - 25 26 - 28 29 - 32 33 - 36
UK 5 - 7.5 8 - 10.5 11 - 13.5 1 - 4.5

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Here's what others have to say...

5 5

The one and only

  • Familiarity: I've put it through the wringer

So good that I bought 6 more pairs. Now I have one for every day of the week

5 5

Stay classy

These sit just above the cuff of the shoe, don't move at all (ie, they don't slip down), and do not cause any hot spots to develop. I know the trend is high-cuff socks, but that is a mistake. Your children, and your children's children, will scold you for participating in that gory faux pas. Do yourself a favor, and get these high quality, low-cuff socks that call no attention to themselves. Wool is real, and you should be too. Thanks

5 5


Let me say it again, Perfection. Fit, comfort, wicking and when I forget to wash them they don't smell bad. Perfection.

5 5

You will not find a better cycling sock.

This sock has it all. Cushioning where you need it. Arch support. Lightweight. Great ventilation. I've biked a ton of miles with these socks and have never had a problem with hot feet. Oh yeah, merino wool whips all other materials for socks.