Leaving your garage door open unnecessarily can be both dangerous and costly. But it's easy to forget that it's open when you're carrying in groceries or the mail. Now you can install a garage door sensor that alerts you to the status of your garage door with audio and visual indicators. Best of all, the Household Garage Door Monitoring System is easy to set up, with the sensor alerting the receiver wirelessly. The garage door sensor mounts near the bottom of your garage door and sends a wireless signal to the receiver in your house when the garage is opened. With its range of 300 feet, you'll be able to place the receiver in any convenient location in your home. If you need to cover a distance further than 300 feet, use the Household Alert Wireless Repeater to extend the communication range between the Skylink wireless devices and ensure the security of your home. The included receiver will control up to four different sensors. Sold separately, you can add a Household Motion Alert Sensor or a Household Door/Window Alert Sensor for security, or a Household Water Alert Sensor for water leaks. If you're planning to add a motion sensor, you can save by purchasing the Household Alert Combination Set. When multiple sensors are installed, only the corresponding zone LED will flash, so there will be no confusion. In addition, you'll know which zone is being triggered by the number of beeps emitted in succession. If you're planning to leave your garage door open while you work in your garden or on your car, the audible alert can be muted easily.