This software is used to calculate the two-speed gearbox in the design of mechanical transmission system, also known as machine design or detailed machine design. It is based on the theme of Ho Chi Minh City Polytechnic. This software includes the calculation and distribution of transmission ratios, belts, chains, straight toothed teeth, inclined teeth, taper teeth, screws and screws, axes, and rollers. The results may be wrong about 3%. Particularly, the axis calculation is being completed and will be updated later. Sometimes the software crashed because of many downloads and unprogrammed program, hope you sympathize, the team will improve gradually through the following updates.