The product can be used to replace the traditional peephole, or be installed in the door after the hole is made. It is suitable for offices, villas, courtyard and unit family places. Features: 2.4G all‑digital frequency hopping and encryption technique, whose unobstructed effective range is 30‑100 meters/98.4‑328.1ft, with strong anti interference ability. If there is an obstruction such as a wall, the distance is only 15‑20 meters/49.2‑65.6ft. 7 inch colorful LCD and 0.3MP camerais used in the indoor unit to display the premium images. The indoor monitor can take pictures automatically and store about 100 photos and automatically take photoes with time. The brightness, sound volume of calling and ringtone of the indoor unit can be adjusted. The indoor unit can display date and time. The standby time of indoor unit is one to two months, and can also work with power plugged in. The outdoor unit is full-touch waterproof. Outdoor controller can unlock under the condition of both powered on andoff. There are 4 built-in chord music ringtone, and the ringtone and volume can be selected. Hands-free calling and intercom functions are equipped and the electric lock can be remotely controlled. The indoor and outdoor both use the BL-5J li battery which is convenient to buy. Specifications: Outdoor Camera: Working Rate: 2402-2483.5MHz Transmitting Power: 18-23dBM Camera: 1/4in CMOS Working Current: 300mA Standby Current: 20-30mA Battery: Rechargeable Li Battery (Included) Battery Capacity: 1320mah Standby Time: 2 month Adapter Output: DC5V/1000mA Indoor Display: Screen: 7 inch TFT LCD Sensitivity: 90dBm Working Current: 250mA Standby Current: 20-30mA/3.7V Battery: Rechargeable Li Battery (Included) Battery Capacity: 1320mah Standby Time: 120h Adapter Output: DC5V/1000mA Working Temperature: -15℃- +55℃ Working Humidity: less than 85% Indoor S Indoor Size: Approx.225 x 130 x 24mm / 8.86 x 5.12 x 0.94in Outdoor Size: Approx. 168 x 110 x 65mm / 6.61 x 4.33 x 2.56in Pacakge Weight:816g/28.8oz Note: The battery needs to be charged for more than 7-8 hours, the outdoor unit can be used for about 20 days when the battery is fully charged, and the indoor unit is only 1-2 hours. It is best to connect the power supply to use the battery as a backup power supply. .