Filter Minder® Fuel Filter Indicator - T Fitting Model 56501 (SAE #6 5/8 - 18 UNF thread) 56501 (SAE #8 3/4 - 16 UNF thread) 56501 (SAE #10 7/8 - 14 UNF thread) All fittings are 45 degree flared. How Does It Work? The indicator monitors the suction side fuel filter on diesel engines. The yellow position indicator progressively fills the window as fuel filter restriction increases, locking at the highest restriction. The fuel filter should be changed when the indicator reaches the red zone. Specifications Operating Temperature: -40 to +250°F (-40 to +121°C) Calibration: 6, 8.5, 10 and 12" Hg (20, 29, 34 and 41 kPa) at red zone Accuracy: ±10% Material: Chemical resistant nylon Dimensions (Indicator only) Length: 63.7 mm Diameter: 32 mm Port: 1/2 - 20 Straight thread o-ring   HOME WHAT WE DO HISTORY CAPABILITIES PRODUCTS CONTACT   Engineered Products Co. 2940 Airport Blvd. Waterloo, IA 50703 Ph: (319) 234-0231 Fax: (319) 234-8922 info@filterminder.com