Features: brand new and high quality High decibel door and window alarm, suitable for anti-theft use in homes, hotels, rental houses, shops, storefronts and other places. The appearance is simple and atmospheric, and the product is easy to operate With low voltage prompt function. The LED on the surface of the host lights up red, which means that the battery needs to be replaced. Stick the main unit and the magnetic strip on the door frame and door panel respectively, and the distance between the two should not exceed 1cm.Turn on the toggle switch on the left side of the main unit to ON, the product is in standby state. When the door is opened and the distance between the host and the magnetic strip exceeds 1cm, the host will immediately send out an alarm sound above 125DB. The door closes and the alarm sound stops. In addition, the presence of young children at home can also be used as a wake-up call. When the child opens the door to go out without permission, the parent can immediately hear the alarm and make an effort to prevent the child from going out without permission. Specifications: Item: Door Sensor Host size: approx 75x38x11.5mm/2.95x1.5x0.45in Magnetic strip size: approx 33x11.8x8.5mm/1.3x0.46x0.33in Weight: 31g Decibel: 125dB Material: ABS Battery: LR44x3pcs Color: White Material: Plastic Note: Due to the problems of lighting effects and shooting angles, there will be certain tolerances in the product, please understand. Please allow 0-1cm error due to the manual measurment. The button cannot be placed on an iron door because it will interfere with the signal. Package includes: 1PC x Host 1PC x Magnetic Strip