Avometer “Universal AvoMeter” multimeter, manufactured by A.C. Cossor / AVO Ltd., England. Portable analogue electrical test instruments designed for measuring voltage, current, and resistance in both A.C. and D.C. circuits. Widely used by electricians, radio engineers, and military technicians for servicing electrical equipment, communications systems, and industrial installations. Rugged bakelite-cased instruments typical of professional field testing equipment. Mid-20th century, c.1940s–1960s.