Marine Aluminium Framed Port Light OpeningYou will need to come in to the store to actually examine these units. You will be astonished at the quality for the price. Firstly, the alloy frames are hydraulically factory pressed. They look like they have been extruded around corners! The frames themselves look that they were made for much larger openings such is the sturdiness. The "lights" (or window) made from 3 8" (9mm) thick glass which is dark (smoked) grey.