What’s in the box? QTY 4 - Swivel Casters (Corner kit includes six casters.) QTY 4 - Caster Washer (Corner kit includes six caster washers) Step 1: Insert stem of casters through washers. Step 2: Thread each caster all the way in to the insert so that no threads are exposed. *Failure to do so will result in the caster failing and causing damage to the leg.