Drip channel drains water to the front of the siding to eliminate wood rot. Wide trim ring, removable template, large flange, and level lines. Injection-molded UV resistant polypropylene for impact. Molded in screen prevents insects and bees from nesting in gable vent. Molded in screen cannot become unglued. Deep wood grain finish enhances appearance for a real wood look. Weeping holes prevent condensation or moisture from remaining trapped. Suitable for use with vinyl or aluminum siding, shake, stucco or brick. 44 sq. ins. of net free area for 12" x 18" and 18" x 24". 74 sq. ins. of net free area for 22" x 28". Rough cut opening is 12.5" x 18.25".