This white injection-molded ABS vent grill has been used along with a collector box by many boat builders to ventilate engine compartments. It has 5 louvered openings, and 8 mounting screw holes.
Outside dimensions: 13-1/4" long x 4-3/4 wide. The tailpiece extends into the cutout or collector box 1" from the underside of the flange. Cutout is 12" long x 3-1/2" wide overall, however the tailpiece angles down to 11-3/4" long x 3-1/4" wide.
High gloss white finish. (pictured in both colors for detail)