C.E.T. Enzymatic Oral Hygiene Chews for Extra Large Dogs (51+ Pounds) ?  EFFECTIVE:  Studies show that 80-85% of dogs stop barking in just one week after using our barking collars, 10-15% of dogs stop within the first two weeks. ?  SAFETY & WARRANTY:  Our anti-bark collar is a humane bark collar with a durable buckle closure that complies with ECA safety requirements. Our no bark collars last a minimum of two years, and we provide a 12 month warranty from the date of purchase. We also provide refunds within 30 days of the purchase date. ?  UNIVERSAL SIZE:  Dog barking collar is suitable for all kinds of dogs: small, medium, large. Lenth is regulated from 5 to 19 inches. ?  FAST CHARGE:  Only 1 hour, and your anti-barking collar is fully charged via USB with your computer, car charger adapter, phone charger, or power bank. ?  100% WATERPROOF:  No need to take off the anti barking collar on rainy days or while bathing or swimming.