1PK 4″ Diameter Blue Diamond TPU Wheel Caster With Foot Activated Total Lock Break That Simultaneously Stops The Caster Wheel Rotation And Swivel. Double Ball Bearing Swivel, Black Powder Coated Rig, 2-5/8″ x 3-3/4″ Plate Mount And 300LB Load Capacity. Offers Soft And Resilient Non-Marking Blue TPU Wheels for Quiet And Smooth Rolling Over Most Surfaces. Roller Bearing Sealed Hubs For Long-Term And Trouble-Free Performance.