For use with plastic louvered vent, with two 3" I.D. wire-supported ventilation hoses. Box fastens to vent with screws or pop rivets, then vent fastens to the deck. Corrosion-resistant plastic. Ventilation hose (not included) twists into the bottom of the collector box to form a raised water barrier. All collector boxes are designed for intake or exhaust and meet all ABYC requirements. Installation Hole size: 2-7/16 x 16-1/4 Depth: 4 inches