Stylus pressure scale
Circa 1970. These were made by Sugden Engineering in UK, who were the manufacturers of Connoisseur turntables, which in the 60's were highly regarded by hi-fi enthusiasts, but very simple and basic. Hence the need for a separate scale to accurately weigh the stylus pressure, which was very important.
The working parts are metal. The base is a hard plastic material, probably bakelite.
Most later automated turntables had built in pressure adjustment.