Helps make moving wire shelving easy with the caster kit for wire shelving. Snap-ring around stem makes for easy attachment. Using casters may reduce load capacity for the shelving unit. Four 5″ Hooded Casters (2 Locking) with Bumper?Bumpers help keep shelving unit from damaging walls. 600 lbs. Per Caster (2,400 lbs. total). Caster/Glide/Wheel: Grip Ring Stem Single Wheel Casters; Color: Gray; Stem Type: Grip Ring; Weight Capacity (text): 600 lbs Per Caster (2,400 lbs total).