REFLECTOR PCBM-12-W1 WHITE 3x4 AR1000 MD SPEC. This product is the most popular of PCBMs for work zone traffic control or permanent delineation. It features over 12 square inches of reflective sheets and versatility in both top and side mount placement. Its distinctive brightness provides additional driver response time when driving in hazardous areas day and night. Its applications include, among others, the design of temporary and/or permanent concrete barrier walls.