corrugated steel shutter
1Hurricane shutter — Hurricane shutters are used in hurricane mitigation to protect houses and other structures from damage caused by storms. They are frequently constructed from steel or aluminum, but homeowners sometimes use the low cost alternative of plywood. The …
2British hardened field defences of World War II — Hexagonal pillbox (type 22) British hardened field defences of World War II were small fortified structures constructed as a part of British anti invasion preparations. They were popularly known as pillboxes by reference to their shape.[1] Con …
3History of the single-lens reflex camera — The history of the single lens reflex camera predates the invention of photography in 1826/27 by one and a half centuries with the use of a reflex mirror in a camera obscura first described in 1676. Such SLR devices were popular as drawing aids… …
