Strong signalThe signal can penetrate obstacles such as doors and walls very well. With sufficient doorway up to 300m in open area, Charlmein wireless doorbell is perfect for 2-storey villas with garden, office, commercial premises. Waterproof Wireless Doorbell The garden doorbell is made of high quality IP44 waterproof material. Operating between -30C and 70C, the radio doorbell is suitable for outdoor use. The radio doorbell can withstand rain and snow, for example. 36 melodies and 4 volumes Huge ringtones ranging from standard DingDong Carnon to animal noises, jingle bells, etc. in good sound quality are available. The volume is easily adjustable in 4 levels from 25 dB to 85 dB. 2 transmitters and 2 receivers The Charlemain wireless doorbell set uses an independent numeric code system, saving you the worry of possible interference with your neighbours' system. You get 2 transmitters, 2 receivers, screws, tape, mini screwdriver,This product does not include batteries, which must be purchased separately