16 channels35 meter range (open air)Traditional "ding dong ding dong" tune for front door and 'ding dong' for rear doorMylar speakerCompact size and modern design12 months battery lifeLow costTechnical specification:Operation voltage: 3V DCBattery: 2 x 'AA' size Sound level: 80dBProduct weight: 92 grams (transmitter battery included, receiver without battery) Number of tunes: 2Product dimension: receiver: 118 x 85 x 39mmOperation temperature range: -10 to +50 degrees CComply with FCC/CE/EMC requirementOperation frequency: 315/433.92MHzG.E Lexan plastic resin with UV resist charateristic used for the button