SURFOU Door Chime Door Sensor Chime with Adjustable Volume 1000ft Range 55 Chimes Mute Mode LED Indicators Easy Installation Door Open Chime for Business Home When Entering,White 1 Receiver+1 Sensor June_2023_update LED Display Vehicle Voltmeter We June2023_cocoonwix LED Display Vehicle Voltmeter We engineered this car charger with the voltmeter to keep you informed of the car’s health Stylist for Tablets door sensor will automatically trigger the receiver when the two part of ransmitter is separated and the receiver will alerts immediately whenever the door or window is opened you can add multiple receivers and transmitters of the same model to expand your door chime system