The Zero/Sports Exhaust manifold is designed to increase torque response of the vehicle’s low and high end Performance. These headers are popular among the circuit racing community in Japan, and are quickly gaining popularity in the States. •Made of Stainless Steel SUS304. •Includes: thermo-vantage tape, thermo-sealed tape, gaskets, volts/ bolts, & Japanese instructions. •Main pipe: Φ1.70" Gathering section: Φ2.37", Pipe Form: 4-1 style