1) High quality PE engineering plastic bed head and end are beautiful andgenerous, freely installed and removed and stable.2) The bed surface is shaped one for all by cold rolled steel plate which is stable and reliable.3) The side rails IS MADE OF aluminum alloy which can be fixed upward and downward. 4) ABS hideway crank, screw-pole is equipped with limited protecting component.5) Four truckles adopt125mm central control system, which are stable and reliable.