The MISCO Palm Abbe handheld digital refractometers, Nos. DEF-201 and DEF-202, come designed specifically for testing the concentration of urea-based Diesel Exhaust Fluid (DEF). This straightforward refractometer test requires only a few drops of urea-based Diesel Exhaust Fluid, and a couple of seconds, to obtain a digital reading of urea concentration with a precision of +/-0.1 percent by weight. Optional accessories include a rugged storage case, protective armor jacket and NIST-traceable calibration certification. Additional measurement scales for fluids such as antifreeze, battery acid and brake fluid can be custom-programmed into MISCO tools. Made in the USA.