Sock Q36.5 Plus You GrayThis is a cutting edge ultra lightweight winter sock constructed with superior natural thermal silk and merino wool yarns. Sock Q36.5 Plus You GrayThe sock follows the same lightweight-density construction techniques of the Ultralight adapted for use in colder weather conditions: the addition of silk (rarely used in cycling socks) to the merino wool increases the thermal properties of the fabric, while at the same time significantly reducing volume and weight. 37g per pair. cuff length 13 cmNote that this wool-silk yarn mix will shrink slightly (although not enough to require a size larger than usual).Finally, the zero-wrinkle contoured fit is recommended to cold wash the sock before first use.