Gibson Power Tip Transom mount Marine Mufflers, Rolled Edge Tip, 4-in. inlet, 4-in. overall. Tested with minimal or no power loss. High quality, Stainless construction. OEM style transom or clamp on mount. Utilizes water to dampen the sound. 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. Certificate of Origin Installation Instructions Warranty