A range of D-sub IDC Plugs and Sockets from MH Connectors with 9, 15, 25 and 37 ways respectively:. Plugs with 3.1 mm diameter holes: 821-2857 , 821-2850 , 821-2854 , 821-2863 . Plugs with UNC 4-40 Cinch Nuts: 821-2866 , 821-2860 , 821-2879 , 821-2872. So