ABLEGRID® Portable Wireless Doorbell with 900-feet, 52 Chimes, IP44 Waterproof Transmitter, 4-Level Volume with LED Indicator Doorbells, No Batteries Required for Receiver ( FX-B7 );

Long Working Distance 
The wireless doorbell support 900feet (274m) operation range in open space. 

IP44 Waterproof Transmitter
The transmitter is waterproof, so you can install it on the outside for your convenience.

Easy to Leave Message
There is a compartment at the bottom of the transmitter that you can delivery some news to your visitors or they can leave some message to you.

Easy Installation
Just plug receiver into an electrical outlet (no batteries required for main receiver) and install the transmitter.

Four levels sound for your choice: 
4 levels of adjustable sound volume give you complete control over the sound of your door chime. Good option for nap time without disturbing your infant or young child when they are asleep.

Specifications:
Receiver Working Voltage: AC110V(US)/AC220V(EU UK AU)
Battery in Transmitter: 12V 23A alkaline battery
Operation Range: over 900 feet (Open Space) 
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 other electronics. Doorbells can work within 900 feet in open and non-interference environment. Generally, it can work within 200~700 feet through the metal security doors and walls depending on the specific using environment. Please do install them within environment with less obstacles.

Package Content:
As the picture shown.