All of vehicle crash tests use high-speed front and side impacts to verify vehicle safety, but rear low-speed strikes are more common by car & people. Vehicles that do not set up the "back bumper inner iron" (referred to as the inner iron inside) are much more expensive for repair than the installed vehicles. The reason is that there is no rear iron to resist the impact. The chassis and the tailgate cover absorb, and the sheet metal cost has always been more expensive than the light-changing parts.

After installing of the aluminum alloy inner iron is only required to replace the crushing columns on both sides after impact. Because the aluminum alloy rod retains the aluminum elasticity; can absorb a buffering by the aluminum alloy shaft & reduce the fee for maintenance of impact force.

The design of the installed aluminum alloy inner iron bar and the collapsed car body does not interfere, and the outer plastic retaining bar also has a distance, which could maintain the softness of the outer plastic retaining bar and maintain the function of the plastic protector to protect the pedestrian.