Features 1) Z-4051B: a) Systems composition: 4 sensors / control box / buzzer / numeric LCD display b) System activated automatically when reverse gear is engaged. c) Detection distance 0.10m to 3.00m d) Acoustic signal increases in frequency when obstacles move closer within 1.50m e) Numeric display from 3.00m to 0.35m f) 7 LCD lights under 3 color cover(green, yellow and red) turn on in order when obstacles move closer within 1.50m g) Obstacle orientation indication 2) QZ-4052B: a) System composition: 4 sensors / control box / buzzer / numeric LCD display b) System activated automatically when reverse gear is engaged c) Detection distance 0.10m to 3.00m d) Acoustic signal increases in frequency when obstacles move closer within 1.50m e) Numeric display from 3.00m to 0.35m f) 7 LCD lights under 3color cover(green, yellow and red) turn on in order when obstacles move closer within 1.50m g) Obstacle orientation indication 3) QZ-4053: a) System composition: 4 sensors / control box / numeric LCD display with built-in buzzer b) System activated automatically when reverse gear is engaged c) Detection distance 0.10m to 3.00m d) Acoustic signal increases in frequency when obstacles move closer within 1.50m e) Volume Hi, Low, Off optional for acoustic signal f) Numeric display from 3.00m to 0.35m g) 7 LCD lights under 3color cover(green, yellow and red) turn on in order when obstacles move loser within 1.50m h) Obstacle orientation indication 4) QZ-4061: a) System composition: 4 sensors / control box / numeric VFD display with built-in buzzer b) System activated automatically when reverse gear is engaged c) Detection distance 0.10m to 3.00m d) Acoustic signal increases in frequency when obstacles move closer within 1.50m e) Volume Hi, Low, Off optional for acoustic signal f) Numeric display from 3.00m to 0.35m g) 7 VFD lights under 3color cover(green, yellow and red) turn on in order when obstacles move closer within 1.50m h) Obstacle orientation indication