Breathable Elastic Nylon Material Fit for Most Size Use for Sports · Non-slip & Silicone inside Unique design that has silicone in side, add the friction, so that non-slip. Adjustable Tightness & Perfect Thickness·  Soft and Comfortable Made from quality breathable material Easy-to-use crisscross Hook strapping attaches anywhere along the entire sleeve. Not thick, not thin, this make it perfect to wear in your shoes.· Adjustable Tightness & Perfect Thickness Easy-to-use crisscross Hook strapping attaches anywhere along the entire sleeve. Not thick, not thin, this make it perfect to wear in your shoes.