roof's ventil stent part 1, Material: steel 2, Processing method: stamping,welding, zinc electroplating ... , brass, plastic etc.Making process:Stamping, deep drawing, bending, punching, laser cutting, threading, welding , tapping, riveting, grindingSurface treatment:Hot galvanized, polishing ... , (IGS, STP, STL and X-T) roof's ventil stent part