... for DVR or extra monitor;2, Four camer Video inputs to connector Front, Rear, Left and Right four cameras;3, Front camera ... 6, Press front switch to make front camera working all time till other acction is done ... X1 front camera; X2 L&R Side Camera; X1 Back-up CameraSpecial Features:1, DVR for front camera is optional ... ;2, Other 170 Degree Mini CCD Camera is optional at ...