As a team of animal lovers, safety is top priority for us. The Hub is built with sensors that detect even the slightest pressure and back off — sort of like elevator doors, but more sensitive! The safety sensors stop the tray from moving if they sense repeated resistance (if your dog is eagerly using a muzzle or paw to get food out of the dish, and keeping it there even when the tray starts to retract). The tray will attempt to retract five times, stop completely, wait for ten seconds, and then attempt to retract again.