The present invention provides a buckle and frame for a restraint system resisting to a harsh environment. The buckle comprising a frame having a base wall, the base wall includes a debris exit opening; and a cover which encloses the frame and forms at least one vent opening and at least one passage which couples the debris exit opening to the vent opening. Debris, dust and other foreign objects which find there way into the buckle are not necessarily trapped but rather are presented with a means of exiting the buckle via the vent opening.