The RetroTrip has been designed and approved for use on many major Historic or Retrospective rallies to fill the vacuum left by the shortage of mechanical tripmeters. Those competitors who could source a genuine period tripmeter with the correct functions and with sufficient spare parts to get it calibrated accurately were felt to have an unfair advantage. The RetroTrip has the functions and instant 'one in a thousand' calibration accuracy for any wheel changes etc plus can be seen to be 'fiddle-proof' because of the old-style electro-mechanical clicking digits, hence its widespread approval. The RetroTrip can be used with a wide range of motion sensors: the wheel type sensor or speedometer type sensor being the most popular. These are fitted as directed by the separate instruction sheet.The tripmeter case is isolated from all connections so positive and negative earth vehicles present no problems. ALWAYS AVAILABLE FROM STOCK AT THE BELMOGSHOP