This wireless sentry sensor from STI lets you know when your garage door or overhead is opened or closed. Device comes with a 4-Channel receiver and operates up to 1000 feet (305m). Includes a supervised battery and signal reception to let you know what is happening while it is happening.
Includes the 4-Channel Voice Receiver (STI-V34104)
433 MHz wireless frequency
Includes one 3 volt lithium battery
Magnetic contact with 18 inch lead for irregular installations