Features
1.2.4GHz digital frequency hopping and encryption technology, transmission distance up to 300 meters in open area, robust anti-interference;
2.Clear night vision:  can capture image in low-illumination environment. This model is still very clear in 5m, while the genral vidoe door phone not clear exceed 1m.
3.Rain shield for the outdoor camera is available;
4.7 inch Digital TFT color panel;
5.High-strength tempering glass,  abrasion resistant and scratch, longer working life;
6.High Sensitivity touch keys
7.Monitor, wireless unlock, hands-free call and talk;
8.16 chord melodies and melody volume is adjustable;
9.Date and time are showed on screen;
10.Indoor monitor store up to 100pcs pictures, pictures mark date and time;
11.Brightness and talk volume are adjustable
12.BL-5J battery of camera and monitor is replaceable and rechargeable;
13.Outdoor camera has two work modes:  
1) Pl ing in the power adaptor. 
2) Using battery, it can works about 15 days. 
14.With Wireless unlock control ,Tamper alarm function;
15.One outdoor camera supports up to 3pcs indoor monitors and vice versa;
16.The outdoor unit with the function of tamper alarm, and if you keep pressing outdoor calling key more than 5 seconds, will turn off battery battery’s power, once again turn on power.       http://www.doorbellalarm.com/