SadoTech  Model CXR Wireless Doorbell with 1 Remote Button and 2 Plugin Receivers  Operating at over 500-feet Range with Over 50 Chimes, No Batteries  Required for Receivers, (Black), Fixed Code C Series.

• WIRELESS DOORBELL KIT: Includes everything you need for DIY  installation – 1 outdoor remote doorbell transmitters and 1 plug-in  smart doorbell receiver, double sided tape, anchors, screws. An A23  battery is included and will last for up to 3 years.
• EASY TO SETUP: Our portable doorbell easily pairs and connects so you  can make your wireless doorbell battery powered. Customize it by simply  selecting frommore than 50 doorbell chime sounds. Has 4 volume settings,  perfect for naptime or parties.
• LONG RANGE: Our patented technology uses the highest quality microchips  and does not need wifi or bluetooth. The signal from the wireless bell  ranges up to 1000 feet. Great for large homes, apartments, offices, and  warehouses. U.S. Pat. No. D800005
• SMART TECH: Not only have we made the traditional door bell ringer  wireless, but we made it smart too. It will remember your customized  settings and has sleek, modern LED lights that illuminate and blink for  guests to easily spot at night. Truly reliable and weather proof, will  operate between temperatures of -4F to 140F.
• VERSATILITY: Our wireless doorbells work great for any occasion -  apartment homes, townhomes, small businesses, warehouses, offices and  condo properties can benefit. Whether you're using it outdoors for your  front gates, back fences, or mailboxes or indoors for teachers seeking  helpful classroom organization and management, there is always a good  use for SadoTech