The PSI-450 Rigid Inflatable dock shelter is the ideal choice to allow complete, unobstructed access to the rear of a truck/trailer for easier loading/unloading. The air bags of the PSI-450 inflate quickly to contact both the top and sides of the truck/trailer for the most effective seal. The inflatable air bags retract back behind the protective curtains when not in use. The unit is supplied complete with bottom pads and heavy-duty, structural steel protective guards.