Aetertek AT-215 Strong Vibration Pet Training Collar for 1 Dog As 1 dog training collar system( can be upgraded as 2 dogs training if add extra receiver) Rechargeable and water-resistant(not waterproof) receiver, pls DO NOT wear this trainer when swim Strong shock + weak shock + strong vibration to get your dog's attention, suitable for dogs from 15 to 150 pounds Solid remote control to 600 yards550mand signal can pass through walls and fences Very easy to use, big and easy to push buttons