This is the "Set of 8 Caster Covers for Carry Cases." Are the casters on your carry case, which is convenient for travel and business trips, damaged? Simply put these covers over the casters of your carry case to prevent noise, wear, and dirt, and to make your casters last longer. These are silicone covers. By removing the covers at the entrance, you can bring your carry case indoors cleanly without dirtying the floor. Furthermore, they reduce the rattling noise during travel, so you can use them without worry during early morning or late night travel, or in quiet places. Made of soft silicone material for a secure fit! Washable and easy to care for ◎ Please note that these are for double casters. Material: Silicone (elastic) Color: Black Size: Diameter: Approximately 5cm, Outer width: Approximately 1.5cm *Not compatible with single-type casters. *Please check the shape of your casters before purchasing.