Seam Sealers are designed to match perfectly with the 'Pennsy' stone wall system. Seam sealers blend & cover butt seams as well as give the appearance of structural integrity. Ideas & instructions included. Each measures 8¼" high by 1¼" wide x ¼" thick. 'PENNSY' O-SCALE SYSTEM is a fully integrated system featuring the classic dressed block pattern of the Pennsylvania RR. Each component matches with each other to create a limitless combination of masonry construction. INSTRUCTIONS FOR SEAMING FL6150 (FL8150) INTERLOCKING WALLS: To fit FL6158 to the 'Pennsy' walls, the seam sealer must be trimmed. A section measuring 1-3/8" is cut from the lower portion of the seam sealer. Using white glue, glue the seam sealer back together OR simply remove the concrete pedestal base. VIRTUALLY EFFORTLESS!