[Rechargeable, Waterproof Receiver Collar] MASBRILL dog fence system comes with 2 waterproof, rechargeable receiver collar that comfortably fits dogs 8 lb and up and adjusts to fit neck sizes 6-28 in. [Beep&Static Shock Modes Warning] When the pet approaches the boundary line you set, the collar will first beep to notice your pet. If he/she continues to approach, it will trigger electric shock accompanied by a beep. [100-Level Signal Adjustable] You can adjust the signal level through "+, -" on the transmitter, once you've laid out the boundary, the higher the transmitter's signal level, the less the dog's range of movement, which means the collar will beep sooner as the dog approaches the boundary.Transmitter will intelligent alarm when connection is bad or the wire is broken, find the problem in time.