Physen Model CW Waterproof Wireless Doorbell kit Operating at 1000 feet Long Range,4 Levels Volume and 52 Melodies Chimes Black,No Batteries Required for Receiver Energy Saving& Durable&WaterproofPowered by 12V 23A battery, the transmitter is tested to ensure up to 10,000 times of press for daily use, no need to replace battery frequently. IP44 dustproof and waterproof rating; works between -7.6F to 149F; withstands various harsh weather conditions. Long Working Distance:Generally, it can work within 200~700 feet (1000 ft in open area) through the metal security door and wall.Wireless range may varies depending on construction and materials.please do not mount the push button on metal materials. Sound Volume & tune: Vol can be set to 25db(no noisy class)-110db(loudest).4 level volume adjustable with 52 charming melodies available, you will never be bored with terrible doorbell ringing again , both perfect to look after the young and the old. This can be specially used as professional pager for the old. When an old man meets with an emergency,he just needs to slightly press the transmitter button, his family can receive his signal for help Flexible design according to your actual needs. You can choose the quantity of transmitter and receiver as you like, which can be freely matched with each other. No matter in the bedroom or on the balcony, you will never miss any visits from outside of your door 2 remote push buttons and 3 plug-in receivers for DIY your house and you can program each push button to a different tone so you can know which door is someone at. Wide Applicability:Take care of your family,for the elderly who is with bad hearing,this doorbell can allow immobile or bedridden patients to conveniently to contact their loved ones when they need help.They can hold on hand or put on the wall for theirs convenience.When the button is pressed, the transmitter and receiver flash at the same time with obvious brightness.