The B-Series door is a steel stiffened door incorporating all the design features of the L-Series door. The stiffeners are welded to the face sheets 4"(102mm) on center vertically and are located 6" (152mm) on center horizontally. The void areas between the stiffeners are filled with fiberglass. High gloss paints should be avoided especially on B-Series doors. The welds used to hold the stiffeners in position will be visible when high gloss paints are used.