Set of 4 Grey Nonmarring Casters for Garment Rolling Racks (Items #6100, #6117, and #6120). These 4" diameter casters are durable and will provide you with a smooth rolling experience when using your Garment Rolling Rack. Includes nonmarring bumpers that prevents damage of walls and fixtures by rack frame. Casters can be used with or without included bumpers. This set of casters includes two locking casters and two non-locking casters. For use with #6100 - Round Tube Salesman Rack, #6117 - Z Rolling Rack, and #6120 - Z Rack Hanger Management Rolling Rack only. The 2 1/4"L threaded stem fit 1/2" rack hole. Priced and sold 4 casters in a set.