Dyn-O-Mate clamshell-style access doors are available insulated or uninsulated and tested to withstand 20 in-WG. Positive pressure and 10 in of negative pressure. They feature a closed cell Neogasket and a bond to the inside plate that prevents leakage. Conical springs between the two-plates provides for easy installation and high impact plastic knobs are designed to avoid stripping and allow a tool-free operation. A template for duct-opening cut out is supplied to insure proper hole size.