Bolt on exhaust end cap that will make your stock silencer a USFS approved Spark Arrestor Designed using the latest CAD design software to offer maximum performance Very quiet and very light When tested by Enduro Engineering, there was no�power loss from the stock end cap found The screen type spark arrestor makes maintenance very easy Simply remove�two bolts and the screen can be removed for replacement or servicing The easy access to the screen is great for riders that use their bikes for closed course and off- road, no need to have two silencers