Duct Access Door; Type Round, Leakproof, Insulated; Door Size 8 Inch x 4 Inch; Finish Zinc Plated (Spring/Carriage Bolt); Top Pattern Scoriated; Options Panel, Gasket, Spring, Knob, Bolt, Template; Inclusions/Features Panel, Gasket, Spring, Knob, Bolt, Template; Duct Size 7 to 9 Inch; Material Stamped Steel (Panel), Neoprene (Gasket), Molded Red Polypropylene (Knob); Material Thickness 22 Gauge