vintage Carl Metz VDO OTA fire gauge 1962

Vintage Carl Metz VDO OTA fire gauge from 1962 in used condition. The chrome is strong and will be nice after polish and it is without dents. The diameter is 8 cm and the depth is 5 cm. The gauge is stamped with “Carl Metz, VDO OTA, m WS, year 5.62, DIN“. Made by Carl Metz in Karlsruhe Germany for fire department “Feuerwehr” vehicles. I do not know for what it is. It came from a fire department in Germany with many other “Feuerwehr parts”. On the rear is written “i.O.” which means “in Ordnung” (=OK) so it was tested at some point and does possible work.