These devices were given to larger Chevrolet dealerships in the 30s to measure “jolts” or bumps in the road demonstrating new vehicles. The device does appear to work as intended and moves/spins as intended. The components are brass with a brass housing on top of a cast iron base. Far from museum quality, multiple flaws. The outer ring that holds the face plate glass is misshapen from damage. Face glass is broken, and missing the 2nd half. Glass appears to be standard 1/8th in thick. Back glass is in decent shape, there are two small chips on either side of the outer edge as pictured. Rubber feet are dry but present. It may be better to leave this as is and unpolished, as there are what appear to be stress cracks along the bottom of both sides. Polishing it may further weaken the metal. As is, as pictured. Makes a great display piece.