3a 1st end thread class 20 2nd end thread quantity per inch two 0.070 in. dia safety wire holes on wrenching facility 180 deg apart unjf 2nd end thread series
3a all ends thread class 2.210" overall length includes bulkhead threads, 1.0625-12 unjf-3a; threaded external fluid end connection, 1.625-12 male coupling half unjf all ends thread series