Tig welded from WELD ELL 304L 8GA Stainless Steel. Head plate and turbo flange are CNC cut from 1/2" 1018 mild steel. Jig assembled and back purged welded. Designed with the T3 turbo flange for smaller-quicker spooling turbos. These turbo manifolds are designed for superior strength and performance. Comes with 44 MM waste gate flange. Optional T4 flange.