1.Multifuncional, training the dog how to ring the , protect your door vandalism, can also help emergency signaling;2.300m distance transmission Stable and efficient signal range up to 300m outdoors;3.1 receiver and 2 transmitters, offer more options;4.The receiver unit has 55 ring tones for your Choice. 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: WirelessDoorbell Model: N668Q-2T1-WCharging Type: Pluggable Charging PlugVoltage: 110-220 (V)Power: 0.035-0.2 (W)Operating temperature: -30 C to + 70 CTransmitter water resistance degree: IP55Operating distance: 300 meters (open and without barrier)Number of songs: 55Volume: 0-110 DbFeatures: Eco-friendly, Low Power Consumption, 55 Ring Tones, IP55 Water Resistant, Door Sensor with Wireless Mobile SensorPlug Type:US Plug,it applies to Canada, India, Japan, Mexico, Thailand, Taiwan,the United States, the Philippines and so on.size:Receiver :8*8*5cmTransmitter:6*6cmMaterial:plasticcolour:blackPackage Contents:1 * Receiver 2 * TransmitterOnly 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.