KEY SPECIFICATIONS & FEATURE: 1.Range up to (open air), Max 200 meters 2.The bellpush transmitter is powered by 3V CR2032 3.38different rings to be chosen 4.Frequency:433.92MHz 5.The wireless system makes installation easy 6.With LED flashing signal 7.Receiver: 2X1.5V AA 8.Learning function 9.Battery Lifetime: about 1 year 10.Transmitter IP44