Honda CRF 250 R 2011-2013, Part No. 06-095.FMF.F4AC FMF - 041473 - Slip-on mufflers are customizable with performance tuning inserts and spark arrestor module (sold separately) - Slip-ons have titanium endcap - Meets AMA sound requirements on most models - RCT stands for Resonance Chamber Technology; creates an effect that lowers decibels and increases the life of muffler packing - Internal ducts in the chambers of the RCT system increase volume for improved exhaust flow, resulting in power gains throughout the entire range of power Included Items: (1) Muffler w/carbon fiber end cap (1) 8mm-1.25x22mm Hexhead bolt (1) Sleeve Specs for FMF Factory 4.1 RCT Stainless Steel Slip-On w/Carbon Fiber End Cap - 041473 Color - Primary Silver Style Canister Muffler Type Muffler/Silencer w/o Spark Arrestor Units Each Weight 7.80 lbs Alternate/OEM Part Number(s): 18211385 FMF Factory 4.1 RCT Stainless Steel Slip-On w/Carbon Fiber End Cap - 041473, Incorporating Resonance Chamber Technology. Patented core shape lowers sound level while maintaining maximum power output. Patented canister shape increases internal volume for more sound absorbing material. Patented chamber design to enhance and refine exhaust pressure. Factory Forward Engineering centralizes mass and is less prone to crash damage. Tuned exhaust with optimized core specifications for each application. Comes with the quality, craftsmanship and performance expected from FMF. Meets AMA and FIM sound requirements. QuietCore 94db insert included. Spark arrestor included in muffler. Built 100% in the U.S.A. at FMFs state-of-the-art-factory. Maintenance made easy with the removal of 4 screws on the front end cap. Compatible with stock or FMF header.