Martin Audio CDD12-MAR - Marine 12-Inch Two-Way Install Loudspeaker (Black)CDD is available to custom order as a Marine (MAR) variant, ideally suited to cruise ships and seaside resort applications. It takes the weatherised model and upgrades both the grille and all metal work to stainless steel 316, and for CDD12 and CDD15 marine variants the cabinet is made from UPM formi instead of birch plywood. The CDD12 WR is a weatherised compact, passive two way system designed for installations that require high output levels