SP110 DEF Hydrometer FAST AND ACCURATE: The EZRED DEF hydrometer has one gauge, for quick, accurate and easy to read level readings every time. . EASY TO USE: The Diesel Exhaust Fluid tester uses a proprietary method to provide the most accurate results in an extremely easy to read way.. BUILT TO LAST: This DEF fluid tester is made of strong SAN plastic, rubber, neoprene, and polypropylene which makes it to dirt, grim, and grease . MADE IN THE USA: This DEF fluid tester is made by the most trusted manufacturer of hydrometers in the world, EZRED, located in Deposit, New York. SP110