WT-850N have 7 levels for sensitivity making it easy to control the bark sound to proper degree, and the vibration could be also controlled from 1-7 levels, you just need to choose the right vibrating level for dogs, safe and easy. No more worrying about the water problem when train your dog, the receiver with great waterproof ability can give your dog enough time to enjoy the cool summer, and the comfortable TPU collar could make sure the receiver is fastened. Get the Dog Bark Collar charged when the power is not enough, you don't need to worry about the battery problems, besides, the automatic power saving design could always allow you enough enjoyable time getting together with your dogs.