Evelots House-Training Doorbells, Puppy Potty Training Bells, Black Great training device - dog rings bells that hang from door knob to let you know he/she needs to go outside. Training your pet with bells is a great & successful method. Bells are strategically placed. Measures approximately 23.5"L x .75"W including bells. Trusted vendor. For years Evelots has provided unique products with a 30 day easy return policy, and 100% satisfaction guarantee.