General description The MUMU Two-Way Wireless Intercom is an efficient communication system designed for various environments such as homes, factories, hotels, hospitals, supermarkets, and offices. It features a built-in speaker and allows for seamless communication between an outdoor doorbell and an indoor unit, ensuring you never miss a visitor. Technical specifications Effective transmission distance: up to 300 meters in open space Transmission distance: 200 meters in open space; 5-50 meters with obstacles Outdoor unit power: 4 AA alkaline batteries Indoor unit power: rechargeable lithium-ion battery Standby time: up to 6 months Dimensions: 100 x 60 x 14.8 mm Installation Easy installation with 3M adhesive tape Outdoor unit is easy to install and allows for battery replacement Usage Press the call button on the outdoor unit to ring the indoor buzzer Press the answer button on the indoor unit to communicate with visitors Volume can be adjusted and ringtones can be changed Other