If your dog jiggles this bell, you let him out. This is a perfect alternative to him scratching up your door. Luckily my dog just barks. My other dog comes and gets me and if I’m not paying attention she just goes to the door and pees to spite me. She actually could use one of these but she’d tear it up to shreds. Oh well. Can’t teach that old dog a new trick but it could be a great idea for other dogs. $14.95 at Wrapables.