This is a Stock Exhaust Header for your O.S. FS70 & FS91 Surpass engines. / This is a short, curved exhaust pipe that is threaded at both ends and uses / black nuts to secure the pipe to the exhaust port and muffler to the pipe. / / INCLUDES: One Threaded Exhaust Header Pipe / Two Black Securing Nuts / / SPECS: Overall Length: 2" (51mm) / Outside Diameter: 3/8" (11mm) / Thread Size: M11x.75mm NMH 1-13-92 / / JAL 5/20/98up / ir/jl