Description: Far wireless remote control distance which is up to 200 m/656 feet in the open air, suitable for both household and industrial use. Mobile interphone, Intercom doorbell, For your old father and mother care, guard your pregnant wife, love your baby, and friend visiting. Loud ring tone reminds you the coming of your guests by lovely songs, big and adjustable speaker, clear voice, also can be used as mobile interphone. You will never miss any guests. All day long anti-interference system, avoid interferences outside or between neighbors. Indoor bells are powered by rechargeable Li-ion battery, outdoor bells are powered by 4 pieces AAA batteries, which can last for more than 6 months. Simple and easy wireless installation with adhesive tape, save you troubles and money. Specification: Material: Plastic Size: Approx. 100x60x14.8 mm/ 3.94x2.36x0.58 inch Outdoor Bell Working Power: 4x AAA battery (not included) Indoor Bell Working Power: rechargeable Li-ion battery Wireless Distance: 200 m/656 feet Battery Working Time: More than 6 months Package Includes: 1/2 Pieces Transmitters 1/2/3 Pieces Receivers 1 Piece Screwdriver 1 Piece Adhesive Tape 1 Piece User Manual 1 Piece Charging Cable Note: Pls note that indoor unit standby time is 24~48 hours. Because the power consumption of the internal machine is relatively large, it is generally recommended that always maintain the charge state,and the outdoor unit should be the battery to reinstall. Since the size above is measured by hand, the size of the actual item you received could be slightly different from the size above. Meanwhile, please be reminded that due to lighting effects, monitor brightness, contrast settings etc, there could be some slight differences in the color tone of the pictures and the actual item.