4in1 Remote Small/Med Dog Training Shock+Vibrate Collar 1. The strong static impulse can penetrate the hair of the pet and fabric within 6mm thick. It is unnecessary to let the discharging point touch the skin of the pet. Therefore it is safe for the pet. 2. The static impulse can quickly and effectively curb the improper deeds of the pet. 3. The warning vibration will let the pet associate the vibration with the static impulse. In the end, vibration will achieve the same effect as the static impulse. 4. Both the static impulse and warning functions are set with automatic rest. This is for not reprimanding the pet continuously. 5. Package : 1xRemote Transmitter(with one 9V battery) 1xCollar 1xReceiver 2x1.5V AAA battery 1xTest Light