A Hohm Electrically Operated Working Demonstration Model Chassis of an Opal Car, Reg No.H 4-D66, built for college education in the 1950's, the chassis with working transparent engine, working crank shaft, cylinders, spark plugs, cut away working clutch and gear box, the differential with working steering, working lights and brakes, in good working order overall, on a wooden base, length 113cm