Before the development of the ball hinge, lever hinge mirrors were the available inspection tool. It is a two-handed operation whereby the mirror is articulated using the looped lever-type hinge mounted on the back of the beveled mirror.
The meticulously crafted inspection mirror pictured above is made of brass (manufacturer unknown) and has a brass sliding cover to protect the mirror. It is probably from the post-World War I era.
The mirror is an absolute essential in the inspection toolkit. While it takes a bit of practice to master the mirror and flashlight to inspect areas that are not readily visible, once the skill is mastered, no inspection will be conducted without one. The inspection mirror is most useful as it enables the inspector to see things such as the biofilm and mold in ice machines; the backs and bottoms of deep fryers, scrapping sinks, ware washers, floor mixers, and grills. Inspection of clean-in-place (CIP) equipment in a food plant cannot be done without a mirror. Other uses include peering into ventilation ducts for dust, lint, blockages, and delaminated fusible links. The list of uses is nearly limitless.
This mirror was salvaged from equipment discarded by the Detroit Health Department.