For Tial 44mm External Wastegate Mvs V-Band Flange Turbo44mm External Wastegate Mvs V Band Flange Turbocharger Turbo Product Description: High performance stainless steel wastegate Ductile cast iron valve body to resist extreme temperatures and warping The valve body has fin heat sinks to help dissipate heat and minimize heat on the diaphragm body Material: Steel And Aluminum Includes 11 psi, and 22 psi springs (combination of 33 psi). You can use the 11 psi 22 psi spring alone or combine them together.