Over 2500 beta gages have been placed in use since the first permanent installation in 1950 for sheet material measurements. During the past six years, beta gages have been an important gaging instrument for a great variety of products: paper, plastics, aluminum, asbestos, glass, rubber, textiles, coating of plastics on steel, paint on mirrors, rubber on fabrics, grit on sandpaper, and saturation of asphalt in paper, to mention only a few. Variations of the beta gage are also used for the measurement of density and concentration.