CRS6500 1.LCD display shows three(five or six)direction''''''''s distance at the same time 2.Unique design of flip-up display has acquired the patent. 3.Buzz alarm with Bi......Bi,Bi...Bi,Biii CRS6800 1.LCD display shows three(five or six)direction''''''''s distance at the same time 2.Unique design of flip-up display has acquired the patent. 3.Human voice reporting the Direction and the distance such as" left behind 32in " 4.three alarm mode for option :human voice reporting, buzz alarm,silence. the default mode is human voice reporting