Eaton NoSPIN Detroit Locker, GM 14 bolt 10.50" FF. This unit installs in place of cross pinion, side and spider gears in your open differential case, GM case p/n 6258336 or 6258340. Eaton p/n 225S-10, 1.50" 30 spline axles, of course. Disassembled and inspected, Excellent Condition. No cracks, damage or modifications evident. I was told this had only three thousand miles on it, approximately. It would be difficult to find closer to new without buying new! Summit gets $460, my price $350.