The price is for a single piece, regardless of whether it's for the left or right foot. Wear on both feet, fill in quantity as "2" when ordering These thermal socks are extra wide and thick, designed for use with plaster casts that require wide and thick wrapping materials. So when purchasing, just focus on the length of your feet. The inner length of size S is 24cm, suitable for feet under size 39 The inner length of size M is 26cmSuitable for feet size 40-43 The inner length of size L is 28cmSuitable for feet size 43-46 XLThe inner length is 30cmSuitable for feet over size 47 or for use outside electric scooter shoes