Wagdog No Harm Anti-bark Collar with Adjustable Shock Sensitivity, Warning Tones, and Reflective Strips. For Dogs 5-150 Lbs, Small, Medium, and Large. Complete with Batteries. Humane, effective and easy to use. WagDog Anti-Bark Collar stops unwanted barking with progressively increasing warning sounds and shock stimulus. After some assembly, you customize the sensitivity for your dog and the collar does the rest. The stimulations repeat through 7 correction levels, the intensity gradually increases until the dog stops for thirty seconds. If the continuous stimulus reaches the highest level, the Collar will stop working for 1 minute to protect the dog. Lightweight receiver, with reflective strips on the band to keep your dog safe at night. One Size Fits All - Effective on dogs from 5-150 lbs. Best on shorter-haired dogs.