Wireless, Push Button Door Chime, Rectangular Brass Finish Housing, Battery Operated, Expands Your Carlon Wireless Chime System To Cover Multiple Entrances, Set Sound On Front Of Button, Weatherproof, Can Be Used Indoors Or Outdoors, Up To 150' Operating Range, 32 Selectable Codes, Compatible With All Carlon Wireless Chime Systems Only, Note: Not Compatible With Carlon Doorbell Systems, Uses Two 3V Lithium Batteries Size Cr2032 Included.