--The bells are attached to a sturdy elastic strap that is smooth without any gaps and won't hurt their pets when they need it.

--1 Pet Training Doorbell + 3 Screws

--Size: bell diameter: 3.5cm, length: 4cm, cargo length 18cm, width 8cm.

--Perfect for dog potty training, Housetraining and Houserbreak, it's your way of communicating with your pet.

--The melodious bells are loud and clear, with no cacophony, and can be heard in the distance.

Description:
Name: Hanging Bell

Goods number:Dog door bell
Product Category: Dog Trainer
Material: Brass

Packing list:
1 x Hanging Bell
Note:

Different displays may cause the color of the item in the picture a little different from the real thing. 
Manual measuring,please allow 1~3mm error,thank you.