This app is designed by R/C car fans , Powerful & Multifunction ! - Get all gear ratios possibilities of the gears the user owns - Motor rotates once moving how many distance(Rollout) - Car gear ratio database - Finial gear ratio - Internal gear ratio - Dynamic gear ratio chart - Easy screen capture for share gear ratio chart Calculation moving distance you can accurately set the gear ratio for different types vehicle(eg...Touring, M-Chassis, F-1, 1:12)