This product USES three main spring, a pay a gradient of spring stiffness spring, a total of four pieces of order. Three main spring specifications don't 60 * 9, after a pay spring specifications are 60 * 18, the main pay spring material are 50 crva, length of 1200 plate spring loading, length 565 front-end, front end lug installed aperture Φ 40, back-end lug installed aperture Φ 33