A shock absorber is a device that reduces impact. It is also called a damper, and is used in many situations, such as automotive parts, building vibration control members, industrial machinery, etc. With industrial machinery, it is used so that vibrations, impacts, noises, etc., generated by the speeding up of movable parts such as transfer machines, automatic assembly machines, machine tools, etc. do not affect the performance of machines. Basically, when an object collides with the shock absorber, the piston rod is pushed and the oil in the pressure chamber is compressed to absorb the shock. The absorption characteristics structure is classified into single hole orifices, irregular porous orifices, and porous orifice structures. In order to operate the shock absorber accurately for a long period of time, it is necessary to select a model that meets the conditions of use, and calculate the energy from the type of collision.