Rectangular mirror 54 x 40 of the 60s

Rectangular mirror with slightly beveled edges. It has a label on the back with the words "copper silvering, guaranteed conservation until 20 april 1967...". It seems to me that it also reads saint gobain aniche and a model number. It is in good condition but does not hide its age: small gaps on the reflective surface at the back creating "spots" at the front. A long but not very visible stripe (about 13 cm) and some other scratches that are not very visible. It measures 54 cm by 40.5 cm for 6mm thickness and weighs about 3.2 kg.

Ref. : SA1S1EQV