Features: 1. Easy Installation & Using - Screws and double-sided adhesive tapes included for easy be fixed to the doorframe of the transmitter. Easily plug receiver into an electrical outlet (no batteries required for main receiver). Install just plug it in location you need it to be heard. 2. Classicc Wireless Doorbell - Stylish modern design, artful with simplicity, elegant and unique. Excellent materials keeps itself from getting higher temperature & interference. Waterproof & Dustproof, remote transmitter button is rated IP44 weatherproof. Works between -20°C to 60°C; withstands various harsh weather conditions, acceptable for outdoor use. 3. Long Operating Rangee - Operating rangee up to 660-1000ft/200-300m in open area ensures you to hear the bell and answer the door in time. Either you are occupied a few rooms away or on another floor, in the garden or kitchen, you will always be easily informed when someone is calling from outside, nsures you will never miss a visitor. 4. Multi Use - It is fit for home, apartment, classroom, office, villas and more. You can use our doorbells to train dogs, using it to quiet down classrooms, when you ring the bell, the students will know it's time to move on to the next group, the kids are loving it also. And it can be a paging device for the elderly, can signal for care when they need it most. 5. 45 Melodies & Adjustable Volume - The wireless doorbell offers a wide selection of 45 chimes for your personal taste, you can have a Christmas doorbell during the christmas season, for example, and more. 4-level of volume rangee from 25dB to 110dB to meet your needs for different occasions. Flashing light with audio alert indicators which is easy for people including the hearing impaired to notice. 6.Self-powered No Battery Required - By pressing the outdoor doorbell, mechanical energy is converted into electrical energy when pressing. Specifications: Item Type: Wireless Doorbell. Color: White,Black(Optional). Plug: US/EU. Plug-in Receiver: Function: Temperature Display. Working Voltage: 80-260V. Working Current: 0.1ma. Working Frequency: 433MHz. Selectable Ringtone: 45 Melodies. Volume Rangee: 4 Levels with Mute Function. Decoding Format: 1527. Receive Rangee: Up to 200M/656FT. Size: Approx. 78x72x20mm(HxWxThickness). Transmitter: Waterproof: Ordinary waterproof. Working Voltage: DC 12V/23A. Working Current <25ma. Power Supply: 12V/23A Battery(Not Included battery). Size: Approx. 68x46x18mm(HxWxThickness). Note: Battery is necessary, but self-powered function can make the battery last longer. Package Included: 2pcs: 1 x Plug-in Receiver + 1 x Transmitter. 3pcs: 2 x Plug-in Receiver + 1 x Transmitter