They are plastic

This center cap only fits: CVR1

Wisefab's upper control arm for the BMW E36 and E46

and Green Spring Rated -15 InHg (installed)

IWG75 Dodge Ram 5.9L TD 26psi JRX11 They are plasticDodge Ram Internal Wastegate Actuator (IWG) provides better turbo response and greater sensitivity when managing boost pressures. Designed as a direct bolt on replacement for the factory part, the Dodge Ram IWG is easy to install and requires no special tools or fabrication. Features: Silicone diaphragm with Nomex reinforcement to withstand high temperatures. High grade, billet aluminum construction. Stainless steel rods and connecting clevis for