S. C. Dey & Co. Manufactures Hydraulic Spring Tester. S. C. Dey & Co. Manufactures testing instrument for Material & Petroleum Testing. The Hydraulic Spring Tester is an electric cum hand operated tester loading through pump. It has 150 mm dia. Platen Sizes having 300 mm gap between platens. It is available in both Tension and Compression combined type.