Underwater exhaust mufflers offer the best sound attenuation at a range of 25-30 dB’s. They are suitable for all inboard applications and can be used on gas or diesel engines. Underwater exhaust mufflers come in a vertical or horizontal design, depending on your engine room’s size and configuration and must be installed above the waterline. They are available in a wide range of sizes and colors, including any custom configuration. Underwater exhaust mufflers have the Lloyd’s Register Type Approval.