Always the correct part
The is the O.S. Speed T-2090SC Complete Tuned Silencer Set.
FEATURES: Fits the O.S. 21XZ-B, 21VZ-B, 21-VG, 25XZ, 28XZ and 30VG engines Aluminum construction, polished natural finish EFRA-2089 noise rating Tuned for 1/8 scale offroad truggy applications Pressure nipple preinstalled
INCLUDES: Header Pipe, Muffler, two Long Springs, three Short Springs Engine to Header Gasket and Header to Muffler Gasket
REQUIRES: Fastening to engine and supporting other end of muffler to vehicle's chassis
SPECS: Length: 6.6" (167mm) Diameter: 1.4" (35.2mm) Exhaust Outlet Diameter: 0.31" (8mm