Unique exhaust baffle design increases the low-end power and mid-range pull of your SPARK's 900cc engine. Delivers up to 5hp on modified engines along with significant torque gains. High-strength aluminum construction will survive backfires and meltdowns. Developed on our Dyno and tested extensively on the water, this waterbox features radiused exhaust tubes and dished end caps for optimum exhaust flow. Recommended for use with RIVA Free Flow Exhaust Kits or RIVA Rear Exhaust Kits. Includes detailed installation instructions.