JL Audio M3 Marine Subwoofer Grille - The M3 Series 10in marine subwoofer reflects JL Audio's commitment to top-quality engineering and sound quality. With marine-grade componentry, durable grilles, and outstanding performance, this sub will be a welcome addition to your boat's audio system. 10in 4-ohm marine subwoofer; Injection-molded mica-filled polypropylene woofer with synthetic rubber surround; Centrex polymer basket and grille, with stainless steel back plate; Marine-grade synthetic fiber spider; Includes: One marine subwoofer, One grille,Six stainless steel mounting screws, Six stainless steel washers;