Features:16 channels35 meters range (open air)Traditional "ding dong ding dong" tune for front door and 'ding dong' for rear doorMylar speaker at rear housing to allow flexible cosmetic design for front paneModern designLow costTechnical specification:Operation voltage: 110/230V ACSound level: 80dB (open air at 30 inches distance of same height)Product weight: 114 grams (transmitter battery included)Number of tunes: 2Product dimensions: receiver: 117 x 75 x 60mm Operation temperature: -10 to +50 degrees COperation frequency: 315/433.92MHzComply with FCC/CE/EMC requirementBS or Euro or US plug optionG.E Lexan plastic resin with UV resist characteristic used for the buttonBlister pack