【125 Decibel Loud Alarm】 You will receive 2 black and gray alarms and 2 sensors. Extra large decibel, this window alarm can instantly detect any movement on the door or window, then emit a 125 decibel alarm sound. 【Easy Installation】 Magnetic Wireless Sensor requires no wiring, no screws and can be installed using the included double-sided tape. This siren helps ensure safety. Whether it's your children, your home, your garage or your business, we want to help you stay safe. 【Low Battery Reminder】 The ultra-sensitive low battery indicator also checks the battery life. With low power consumption and a standby time of up to about one year, it's the perfect, affordable addition to your home security. 【Smart Design】 Once the alarm and magnet are separated by more than 15mm, the alarm will continue to sound until you close the door. No indoor alarm setup, wiring, or networking required. 【Peace of Mind and Reliability】This apartment security system is designed to provide additional