Low profile fiber mat permits maximum airflow yet prevents water and insect infestation. 3/4' - lowest profile in the industry. No fabric overwrap or filters to clog or deteriorate. Flexible, easy to handle. Conforms to roof pitches from 2/12 to 20/12. 40 year limited warranty. Includes 2-1/2 roofing nails. Cobra hand nailable ridge vent net free area - 16.9 sq. in./linear ft. Cobra gun nailable ridge vent net free area - 14.1 sq. in./linear ft. Model No GAFCB10520: Size: 10.5' x 20', Thickness 3/4', Type:Hand Nail, Color: Black, Net Free Area: 16.9 sq. in./linear ft. Pkg Qty: 1 Package Type: Sleeve No. CGRV10520: 10.5' x 20', Thickness: 3/4', Type: Gun Nail, Color: Black, Net Free Area: 14.1 sq. in./linear ft., Pkg Qty: 1.