Product description Material: plastic Color: black Waterproof quality: IP55. Working temperature: -30 C to + 70 C. Working distance: 300 m (without barrier ) Operating frequency: 433.92 Volume: 0-110 dB (5 levels adjustable, with mute function) Transmitter battery: 12V 23 One alkaline zinc-manganese battery (built-in)Receiver (length x width x thickness): 6*6*1.5cm Transmitter (diameter x thickness): 7.8*5cm Package 1 includes: 1*receiver, 1*transmitter Package 2 includes: 1 * Receiver, 2 * Transmitter Easy to Trigger- The dog bells just need to be gently nudged or slid across the touchpad to activate the wireless doorbell by nose or claw. The interval between two bells is about 20 seconds. No need to press. Any small or large dog can do it. 2. EASY TO INSTALL- All potty training dog doorbells are wireless. Use 3M double-sided tape to stick the transmitter on the door/floor/wall, also on a circuit board, and place it anywhere you like. Simply plug the receiver into an electrical outlet. The appropriate method is simple and easy to use. 3. Adjustable Sound and Volume- The smart dog doorbell offers 55 ringtones and 5 volume levels from 0dB to 110dB to choose from. Set it to 0dB (mute) if needed. 4. 300m Wireless Range- The front doorbell comes with transmitter and receiver. The transmitter and receiver can be easily coupled. Stable signal transmission and good interference performance. 5. IP55 Waterproof - The built-in waterproof sealing ring can protect the elements inside from water and dust to extend the service life. It can work normally on rainy days.