HEAVY-DUTY CASTERS: The HANDSAMMU's heavy duty casters are made of high-quality Epoxy Esin, bright Epoxy Esin wheels and galvanized steel yokes. These High-Tempertature Bakery Oven Rack Casters are commonly seen on oven racks, bread racks, bakery racks, or any tray or rack that goes into an oven and into a freezer.