Product Material: plastic Colour: black Waterproof grade: IP55. Working temperature: -30C to +70C Working distance: 300 m (without barrier) Operating frequency: 433.92 Volume: 0-110 dB (5 levels adjustable, with mute control) Transmitter battery: 12 V 23 A 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 1.Easy to trigger The dog bells just need to be easily pushed or pushed over the touchpad to activate the wireless doorbell by nose or claw.The distance between two bells is approx. 20 seconds.No need to press. Any small or large dog can do it. 2.EASY INSTALLATION All dog doorbells for potty training are wireless. Stick the transmitter to the door/floor/wall with 3M double-sided adhesive tape, even on a board, and then place it in any place you need.Simply connect the receiver to a power outlet. The appropriate method is simple and easy to use. 3.Adjustable sound and volume The intelligent dog doorbell offers 55 ringtones and 5 volume levels from 0dB to 110dB to choose from. Set it to 0 dB (mute) when you need it. 4.300 m wireless range The pet doorbell comes with transmitters and receiver. Transmitter and receiver can be easily paired. 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 prolong the lifespan. It can work normally on rainy days.