A VARIETY OF FUNCTIONS : The ring doorbell has five functions of welcome / doorbell / alarm / color light / night light.With power-off memory function, the battery is automatically backed up when the power is cut off, and it will remind to replace the battery in time when the power is insufficient.Optional to learn of 32 wireless probe accessories such as infrared, door magnet, vibration, and 8 remote controllers, flexible and versatile. INFRARED DETECTION : The infrared detector has a detection angle of 100 degrees in the horizontal direction and 15 degrees in the vertical direction, and a sensing distance of 2 - 8m/6.6-26.2ft. LONG-DISTANCE USE : Long-distance transmission, reaching 280m/918.6ft in the open field, suitable for larger places and higher floors.A dedicated speaker for independent alarms, with a maximum of 113dB, can effectively deter thieves. MULTIPLE VOLUME AND MUSIC : 4 levels of volume can be adjusted, changing battery memory and other humanized designed, more considerate.8 chord music chip, 40mm big speaker, more pleasant and louder.16pcs doorbell music can be changed at will, which can satisfy different preference. Feature: 1. Colorful LED lights, 4 levels of brightness adjustable, different colors can be used to distinguish multiple entrances, more dazzling and smarter. 2. HD MP3 voice prompts for all modes and operations, making it easy for using. 3. With universal adjustment base, infrared sensor window can be adjusted 180 degrees left and right, 360 degrees rotation adjustment. 4. No need to insert a card, built-in U disk, DIY sound synthesis or recording, mini USB interface connected to computer to download. 5. With power-off memory function, the battery is automatically backed up when the power is cut off, and it will remind to replace the battery in time when the power is insufficient. Specification: Material: ABS Power Supply: Receiver: 3 x AA Batteries (Not Included) / USB 5.0V Power Adapter (Not Included) Infrared Detector: 3 x AAA Batteries (Not Included) / USB 5.0V Power Adapter (not Included) Transmit and Receive Frequency: 433MHz Working Temperature: Receiver: -10-60 Infrared Detector: -10-33 Receiver Battery: Available 5-7 Months (Calculated 30 Times Per Day) Infrared Detector Battery: Available for 5-7 Months (Calculated 30 Times Per Day) Package List: 1 x Receiver 1 x Infrared Detector 1 x Double-Sided Tape 2 x Screw 2 x Infrared Detector Mounting Base 1 x Instruction