4 In 1 Remote Small/Med Dog Training Shock Vibrate Collar Trainer Safe For Pet Package Includes: 1 x Remote control unit, 1 x Adjustable collar, 2 x AAA Battery(Gift), 1 x Test light (Batteries are not included), 1 x Operating Instructions This collar is the best sulotion for small (at least 10 pounds), medium dogs and cats, not for those up to 100 pounds. 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. The static impulse can quickly and effectively curb the improper deeds of the pet. The warning vibration will let the pet associate the vibration with static impulse. In the end, vibration will achieve the same effect as the static impulse. Both the static impulse and warning functions are set with automatic stop. This is for not reprimanding the pet continuously. With the vibration induction power switch in the collar receiver, it will turn on and turn off automatically to save power. It is safe for the pet !!!