REVEX door and window chime, model number HSA-M4B. This chime sounds when a door or window is opened, and can be used for visitor detection or as a security alarm. You can choose from 16 different melodies and siren sounds. This is a new, unused item, but the product has been opened for inspection. Please refrain from purchasing if you are sensitive to items stored at home. [Brand] REVEX [Model Number] HSA-M4B [Functions] Visitor detection, security alarm, volume adjustment (55-75dB/1m), number of chimes (1 time/repeat), melody and siren selection, selection button (13 melodies, 3 sirens) [Batteries] 2 x AAA alkaline batteries (sold separately) Thank you.