WIRELESS DOORPIECE KIT: Contains everything you need for DIY installation - 1 external outdoor doorbell transmitter and 1 plug-in smart doorbell receiver, double-sided tape, anchors, screws. An A23 battery is included and lasts up to 3 years. EASY TO SET UP: Our portable doorbell can be easily paired and connected, so you can power your wireless doorbell on batteries. Customize it by simply selecting from over 50 doorbell chime sounds. Has 4 volume settings, perfect for naps or parties. LONG RANGE: Our patented technology uses microchips of the highest quality and does not require wifi or bluetooth. The signal of the wireless bell reaches up to 1000 ft. Great for large houses, apartments, offices and warehouses. US Pat. No. D800005 SMART TECH: Not only have we made the traditional doorbell ring wireless, but we've also made it smart. It remembers your custom settings and has sleek, modern LED lights that light up and blink so guests can easily spot them at night. Really reliable and weatherproof, works between temperatures of -4F to 140F. VERSATILITY: Our wireless doorbells work great for any occasion - apartments, townhouses, small businesses, warehouses, offices and apartments can benefit from this. Whether you use it outside for your front gates, back fences, or mailboxes or indoors for teachers looking for helpful classroom organization and management, there is always a good use for SadoTech Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin