1.Multifuncional, training the dog how to ring , protect your door vandalism, can also help emergency bell signaling; 2.300m distance transmission Stable and efficient signal range up to 300m outdoors; 3.1 receiver and 2 transmitters, offer more ; 4.The receiver unit has 55 ring tones for . 5 adjustable volume levels from 0db to 110db .; 5.Easy to use (plug and play), it is perfect for large houses, such as villas, apartments, offices, warehouses, etc. Type: Wireless Doorbell Model: N668Q-2T1-W Charging Type: Pluggable Charging Plug Voltage: 110-220 (V) Power: 0.035-0.2 (W) Operating temperature: -30 C to + 70 C Transmitter water resistance degree: IP55 Operating distance: 300 meters (open and without barrier) Number of : 55 Volume: 0-110 Db Features: Eco-friendly, Low Power Consumption, 55 Ring Tones, IP55 Water Resistant, Door Sensor with Wireless Mobile Sensor Plug Type:US Plug,it applies to Canada, India, Japan, Mexico, Thailand, Taiwan,the , the Philippines and so on. size: Receiver :8*8*5cm Transmitter:6*6cm Material:plastic colour:black Package Contents: 1 * Receiver 2 * Transmitter Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.