These are 2mm oversize 2.0 Intake seats for 46 valves.

These are special alloy*..

*Modified M2 Tool Steel, which utilizes a blend of three types of carbide materials to provide outstanding wear resistance for valve seat insert application.  Molybdenum and Tungsten carbides are both harder and more thermally stable than chromium carbides.  They also form a carbide structure to impart more stability to the base material.  Vanadium carbides are also added to provide greater wear resistance without affecting the machinability of the product.  This Iron based insert allows for excellent heat transfer.  T-series hardness run @ 42 Rc and is currently the industry choice when mated with premium or Inconel valves.