From the Manufacturer

The SL-6400-A wireless push button is battery operated and features a polished brass finish with up to 125-Feet transmission range between the push button and the door chime receiver. This push button is mounted to the surface of a doorframe or exterior wall and requires no additional holes to be drilled. Push button battery is included.
Polished Brass Finish
Battery Operated for Simple Installation - Surface Mount
Range up to 125-Feet
with all Heath/Zentih Wireless Door Chimes