This is the M2000SC Manifold (header) from O.S.for use with the O.S..21VZ-B V-Spec and .30VG series engines FEATURES: Spring connect header Polished aluminum with steel springs INCLUDES: One M2000SC manifold Two steel springs for connecting to engine One rubber exhaust gasket REQUIRES: Pipe SPECS 1.2" (30mm) mount surface to rear of manifold Diameter: 0.73" (18.6mm) inner diameter of mount flange 0.87" (22mm) outer diameter of mount flange 0.51" (13mm) inner diameter of manifold pipe 0.63" (16mm) outer diameter of manifold pipe COMMENTS: This is for use with the spring connect pipes and could not be used with the T-2060 Tuned Pipe. wm 3/31/06 ir/jxs