Boot Bolt 7/8″ x 2 1/2″ HHCS, GR 8 Fine Thread-V1. This is the very first style of boot bolt which was changed approximately in 2010 to the new coarse thread. If they are stripped out you can replace with a longer bolt and nut. You will be required to drill out stripped threads on the elbow. For stripped out threads see part #218 as a replacement.