The DRD Spark Arrestor End Cap fits directly onto OEM mufflers of motocrossers and enables the stock exhaust to be easily converted to a spark arrestor/USFS-legal system - perfect for when you ride in state recreational areas that require spark-arrested exhaust. The SA End Cap accommodates the DRD Quiet Core Insert (sold separately) for the noise-conscious customer... or to comply with sound regulations that are popping up at more and more tracks, races and riding areas. The SA End Cap features the signature DRD "D" shape design and is available for Honda, Kawasaki, Suzuki and Yamaha (YZF/CRF/KXF/RMZ) motorcycles.