BROTHERS 63-72 drop trailing arm crossmember with anti-squat mounts is specifically designed for trailing arm trucks that have a 4 drop or more. It increases ground clearance on your lowered truck. Anti-squat bolt-on mounts allow for the use of 5 different trailing arm settings. Lower hole is for factory trailing arm position, and is adjustable for up to 4 degrees of anti squat allowing more drive off of corners for better performance. Designed for shortbed applications with one-piece driveshafts.