... Parking aid, 2.Processing and combining video signals, 3.Four Channel Video input. 4 Channel Video Switcher for Car Security System CL-30256B Product ... introduction:This device functions as an all-round video switcher,it's used for switching images among front view camera,rear view ... ,Western Union or Cach.Factory Photo and Certifications: 4 Channel Video Switcher for Car Security System CL-30256B