... . 4CH Dual Camera Car DVR factory 4CH DUAL SD CARD DVR 4CH Dual Camera Car DVR factory With G-Sensor/ GPS optional 1SD CARD / 2 SD CARD 4CH Dual Camera Car DVR factory Ordering Guide ... , RS232, differential speed interface >> Car black box function, recording speed, position, momentum, acceleration, temperature, brake, reverse, turn, alarm and other important information. >> DC8V ~ 36V ...