A. The set return spring kit includes 4 spare parts of motor governor springs, as shown in the figure. The sizes are 71×7 mm and 43×4 mm. B. These replacement springs are of good quality and fine workmanship. They are relatively convenient to use and install. Replacing the old springs with them can save time and money. C. The governor spring is not an original - factory part, but it is suitable for many engines. It can be adapted to a number of lawn mowers and gasoline engines. The spring may help solve the engine noise problem. D. The adjustment spring is made of durable metal. It is not prone to rusting, is relatively strong and durable, corrosion - resistant, and oxidation - resistant, with a relatively long service life. E. If you have any questions about the extension spring, please feel free to contact us. We will try to provide you with satisfactory service.