With good penetration and long receiving distance up to 300m (opening space). Easy to install and no wiring required. Easy wall mounting with double-sided adhesive tape or screws. 55 optional built-in tones and 5 adjustable volume levels from 0 to 110dB. The transmitter is IP55 waterproof. Perfect for office buildings, hotels, homes, hospitals, etc. Chime range level LED indicator Open alarm Business/Office/Home/Store upon entering Easy to install and no wiring required. Easy wall mounting with double-sided adhesive tape or screws. 55 optional built-in tones and 5 adjustable volume levels from 0 to 110dB. The transmitter is IP55 waterproof. Perfect for office building, hotel, home, hospital, etc. Specifications: Receiving Distance: Up to 300m (opening space) Volume: 0-110dB, 5 levels adjustable Tone: 55 tones Frequency: 433.92MHz ± 280KHz Power Supply: - Transmitter: 1 x 12V 23A battery (NOT INCLUDED) - Receiver: 3 x AAA batteries (NOT INCLUDED) Transmitter Size: 35 x 85 x 15mm