Adjustable to bring rail closer or further away from building For use on corrugated metal siding due to narrow mounting surface Barn door track brackets single box steel finish=galvanized Designed for mounting #5114 or #5116 box rail. Includes 2 lag bolts, carriage bolt and nut. BHMA A138.18. Suitable for use on corrugated metal siding due to narrow mounting surface on sliding door systems. Adjustable to bring rail closer or further away f rom building. 300 lb safe working load. 7.12 inches L x 3.25 inches W x 2 inches D. Can be used with flashing with the 5151 flashing bracket.