Polaris RZR1000 2 and 4 seat Behind the Seat Subwoofer Enclosure for 10 woofer Marine Grade fiberglass; Direct fit Installation; Stainless Steel hardware; Fits XP 1000 and XP4 1000; NOTE: requires external amplifier. Not directly compatible with WP overhead systems;Speakers Not Included SSV Works SSV Works Behind the Seat Subwoofer Enclosure for 10 Inch woofer - RZ3-BSSB10-U RZ3-BSSB10-U UTV Stereo