The Castelli Sfida 13 Sock is a women\'s cycling sock designed for the cold. Super warm soft Merino wool is blended with Polyamide and Elastine to create a super snug fast drying and moisture wicking winter-weight cycling sock. The foot-bed of the sock is created using a Terry knit this creates a thicker than normal, luxuriously soft feel, but more importantly, it equals great insulation, where you need it most. The cuff extends to a generous 13 cm ensuring full coverage and more than enough sock to provide a decent overlap with your winter tights. Sfida translates as challenge dare or defiance, so make a stand defy the cold winter and go ride your bike. Key Features 50% Merino wool blend Super thick and comfy terry knit underfoot 13 cm cuff length Size women\'s S/M - L/XL