Turbine Inlet Flange, Larger rectangular bolt pattern with 4.5" and 2.75" center to center bolt patterns. Bolt pattern is also found on larger GT42 turbine housing and other similar size turbos. Larger than T04 turbine inlet bolt pattern. 1/2" Thick mild steel, precision CNC machined with nicely chamfered edges along with divided center. 4 holes are tapped to use 10mm studs.