lengthy on the job The radio doorbell support 900feet -LRB- 274m -RRB- operation range in unsealed space. IP44 rainproof Transmitter The transmitter is, so you can install it on the extracurricular for your convenience. Easy to Leave Message There a compartment at the lower of the transmitter that you can delivery some news to your visitors or they can leave some message to you. Easy Installation Just receiver into an physical phenomenon outlet -LRB- no batteries required for chief receiver -RRB- and install the transmitter. Four levels for your choice : 4 levels of adaptable stable volume give you sheer bodily function over the stable of your door chime. nifty for nap time without distressing your infant or teenaged child when they are asleep. : Receiver on the job Voltage : AC110V -LRB- US -RRB- / AC220V -LRB- EU UK AU -RRB- Battery in Transmitter : 12V 23A alkaline battery Operation Range : over 900 feet -LRB- Open Space -RRB- Selectable Ring tone : 52pcs Volume Range : 30-110db ; 4 levels NOTE : What You Should Know Before Installation Doorbell 's signal can be effected by metal, walls, concretes and interference signal from another electronics. Doorbells can within 900 feet in unsealed and non-interference environment. Generally, it can within 200 ~ 700 feet through the metal security doors and walls depending on the circumstantial using environment. Please do them within environment with less obstacles. Package : As the picture shown.