... wireless hidden camera and mini button camera13). Wireless receiving frequency: 2.4GHz, 8 channel, manual switchChannel Frequency: CH1-2414MHz; CH2-2432MHzCH3- ... : 1. High-speed USB2.0 Interface, USB OTG 2.0 2. Built-in 1W speaker 3. Audio and video input ... audio channel,video input,battery voltage outputUSB interface:USB 2.0Power adapter and othersBattery:Rechargeable Li battery 3.7VPower ...