Gibson Bullet Marine Clamp on Mufflers were tested up to 1200HP with minimal or no power loss. High quality, Stainless construction. OEM style transom mount. Straight through design. Utilizes water to dampen the sound. These silencers were specifically designed for Large displacement motors such as 500HP, 502, 525, 525SC, 575. and up to 1,200hp. Easy bolt - on installation. The Gibson Marine Mufflers have proven to reduce decibel ranges within and to surpass the 88db limits required by the California SAE J2005 Motorboat Sound Law without compromising power.