Supports reverse eject automatically up app and outputs Hass main control, transmission signal stability, the Perfect state distance can reach 100 , the distance measured by the sea can reach 50 , the car can rest to use Save money and use mobile phones instead of monitors easy to install, wireless connection, no cable Simple operation, support channel switching, no need to worry about signal interference Model Number: TOP-309 Colour:black Material:ABS Size:6 x 5 x 2.1cm Package Contents: 1 x WIFI Transmitter 1 x Antenna 1 x cable Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.