1. Non-magnetic stainless steel main frame and outer flange 2.#8 hand-polished mirror finish to protect against corrosion 3.Adjustable stainless steel hinges for continuous and variable positioning of lens 4.10mm smoked acrylic lens 5.Adjustable acetal turn latches for positive sealing pressure 6.EPDM gasket for ensured watertightness 7.opening optional on 616 model 8.ss316 9.oval opening portlights