16" x 4", Economical, Flat Screen Vent, For Flush Or Surface Mount, Designed For Vents Spanning Between Wall Studs 16" On Center, Galvanized Steel Frame With 1/4" Galvanized Wire Mesh 23 Gauge, Net Free Vent Area 42 SQIN, Overall Dimensions: 15-1/4" x 4-3/4", Rough Opening: 14" x 3-1/2".