12-3/4 O.D. Special Extension Sub, 36 Long, with O-Ring on

12-3/4 O.D. Special Extension Sub, 36 Long, with O-Ring on Pin Thread and box thread to accomodate HP Top Sub with O-Ring. For use between Top Sub and High Pressure Pack-Off Assembly 14,000 PSI Collapse Pressure (15801) f/ Logan Series 150 Overshot.