Amarine-made Boat Marine Stainless Steel Vent - 3 Louver 8-1/4" X 4-3/8", 4 Louver 10-1/5" x 4-1/3", 5 Louver 12-3/4" X 4-3/8", 6 Louver 12-7/8" X 3" All-welded 304 stainless steel construction with polished finish Pre-drilled with six holes for #8 screws. (not included) ventilation systems Pre-drilled with six holes for #8 screws