Set of four stainless steel wheels can be attached to our ProSelect Stainless Steel Modular Cages ZW5500 or X-Tall Modular Cages ZW5550 to provide instant mobility. Great for cleaning and for rearranging cages in a flash. Wheels lock to keep cages securely in place and prevent accidental movement.. Material - PVC and Metal. Size - Each wheel measures 4.5 L x 3 W x 2 H in.3