Flammi 3 Pairs Men's No Show Loafer Socks, Boat Shoe Liners, with Non-slip Silicone Heel Grip 80% cotton, 18% polyester, 2% spandex Imported Soft, comfy, elastic, sweat-wicking, breathable Fit Shoe Size US Men 6.5-10 Silicon grip is on the inside back of the heel, which keeps the socks stay on your feet No Show socks, they are invisible in boat shoes, loafers and driving shoes