The Poly-Planar MS55 Compact Sub Woofer Box is a compact, high efficiency bass enclosure optimized for marine applications. It's small size enables it to be easily mounted below seats, under the gunwale area, behind the instrument panel, or any convenient location. The MS-55 is a self contained bass unit requiring no cutting of panels or holes in the boat interior. It produces solid, deep bass extending down to 40Hz and is the perfect addition to any audio system. The water-resistant MS-55 features a high density, UV stable enclosure and dual voicecoil, high-excursion, 5.25 woofer.