The OEM feet on Favero pizza-reels are not particularly durable, so these are designed to solve that issue. Permanently. I'm pretty sure these won't wear off or tear off, and there is no need to glue them in place with CA like the OEM rubber feet. The black part is very tough urethane rubber. Designed for a specific machine-screw with a flatter than usual countersink angle, installed with nylock nuts, and one-quarter the cost of OEM replacements.