Power Supply Method: Polymer lithium battery Battery Powered: DC5V/1A Working Temperature: -20 ° C~55 ° C Transmission Distance: open space of about 1000m/3280ft, partition walls of 20-50m/66-164ft Working Frequency: B-gear frequency 462MHz, A-gear frequency 434MHz Working Time: Charge once for about 3 days Charging Time: Approximately 5 hours when fully charged Music Ringtones: 38 ringtones Ring Volume: Level 3 adjustment (standby machine volume adjustment key) Call Sound: Level 3 adjust call size (adjust volume key during call operation) Product Quantity: 2Pcs Product Colors: Black, White (optional) Product Size: 116 * 56 * 18mm/4.6 * 2.2 * 0.7inch Charging Dock Size: 70 * 56 * 29mm/2.8 * 2.2 * 1.1inch