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! * One for front & back door or give as a gift to a friend! * Bells are strategically place! Separate strap to make shorter for larger dogs! * Main strap made of polypropylene fiber and measures approximately 24"L X ¾"W not including bells!