The Gerin Model PSB-97 Oil Colorimeter Test Method Provides Visual Examination of Petroleum Insulation fluids Oil color and clarity provide added test data to determine an insulation fluids fitness for further use. The PSB-97 is a very simple, economical, visual tool. Almost unbreakable making this testor suitable for field examination. Ordering Information Call for technical literature, availability and current cost. Telephone: 732-774-3256. Facsimile: 732-774-0274.