Pinit Billhead BACKINGS. 5-1/2 x 8-1/2". .040" thick Museum Grade board. All white. Indefinite Storage. SKU: KAF40BH58 (0)No Reviews yet Add to Shopping Cart Details Billhead Backings 5-1/2 x 8-1/2". ALL WHITE. .040" thick Museum Grade Acid-Free Board. Buffered. 100% Alpha-cellulose board. Indefinite storage. Details Back DetailsBillhead Backings 5-1/2 x 8-1/2". ALL WHITE. .040" thick Museum Grade Acid-Free Board. Buffered. 100% Alpha-cellulose board. Indefinite storage. Reviews 0 Back Ratings & ReviewsNo reviews availableBe the first to Write a Review