All4pet DC-E80 Waterproof Remote Training Collar Expandable to an Two Dog System Total combined 100 levels can be adjusted according to your baby's personality and size The most effective and safest training system with auto-protect mode 330 yards remote control electric shock devices with advanced RF434Mhz technology Power saving design with automatic standby, 4 modes, light, beep, vibration and shock The receiver is rechargeable and waterproof and the remote transmitter is also waterproof