NWT Support Sole white knee-high socks from Birkenstock. Size: US L8-L10 EU 39-41 UK 5,5-7,5 Made with certified organically grown cotton Made in Turkey The seamless compression of this knee-high sock invigorates the legs by boosting circulation. Sitting and standing are therefore made easier. An optimum footbed provides a strong base for the Support Sole knee-high sock. Thanks to the Footbed Comfort Sole from Birkenstock, an ideal comfort level is achieved. The high-quality, certified organic blended cotton offers a soft and comfortable feel.