1.15" anti-reversion exhaust valve. The valve face design allows exhaust gas charge to flow into the exhaust port, while reducing the tendency to back up once the piston has reached top dead center. This effectively gives you a more efficient exhaust port, and is particularly beneficial in an otherwise unmodified head. Made of EN214N stainless steel, with flash chrome-plated stem for use with standard iron guide. Stem is waisted for improved flow, swirl polished, and has a stellite hardened tip. Sold each. Ref: C-RIM106, SEN0071, 12G940, RIMFLOW1.15L, SV300-52.