X-cords Potty Training and Housebreaking bells 100% Adjustable! For All Size Dogs 100% ADJUSTABLE bells can be positioned to fit all dogs form the smallest yorkie to the largest lab. As your boxer grows you will want to adjust the hight to make it easy and stress free for them. Frustration Free installation-Just hang it on the door knob. No nails, screws, or messy adhesive needed Looks great on any door, adjustable. high quality, custom made. We suggest that you get one for every door that your puppy uses 95% SUCCESS RATE Potty train your dog or puppy in just days not weeks. Amazing results our schnauzer mastered it in three days and now uses it all the time Made in the USA with paracord 550 It has a break strength of 550l lbs. will not rot or mildew delivering years and years and years of service