Big Gun Exhaust 13-76111 EXO Series Head PipeBig Gun Exhaust 13 76111 EXO Series Head Pipe EXO Series came from a realization of the need for a bigger and better muffler that could handle the huge demands of the larger, more powerful sport ATV motors. The EXO Series is our ground up approach at just that. A unique hexagon shaped aluminum muffler and stainless steel coned inlet allow for significantly more volume, delivering a louder but tolerable deep sound while also decreasing heat. Precision