This is a set of two optional M2C Racing 4mm Tapered Inner Hinge Pins, and are intended for use with the Mugen MBX6 family of vehicles. These are also the same hinge pins that are used in the M2C Racing MBX6 Anti-Diver adjustable front suspension kit.
These hinge pins are made from hardened 01 Tool Steel, and will give the user insurance from damage to the rear hinge pins. If the pin bends, it will likely bend at the weakest point on the pin, which is at the smallest portion of the taper. Because this area is not in the bushing or arm, it will not affect the movement of the arm. The arm will still rotate around the hinge pin if it binds in the bushing, and the ball on the pin will also allow the the arm and hinge pin to rotate in the bushing, which is the area of least resistance in the system.