New OEM Cummins turbo mounting nut, part number 3056158. Please note that the listing for a pack of 4. The item is depicted as #1 in the above diagram.

Compatibility Includes:

K19, KTA19 G CMEICS K123, KTA19GC, KTA19GC CM558, QSK19 CM2150 MCRS, QSK19 CM2350 K105, QSK19 CM500, QSK19 CM850 MCRS, QSK19G, NH/NT 855, NT495, NT743, NTA855 N106, G50, K50, K50-DPM, QSK50 CM2150 K107, QSK50 CM2150 MCRS, QSK50 CM2350 K108, QSK50 CM2350 K130, QSK50 CM850 MCRS, QSK50 DF CM850/CM2150 MCRS