Many modern diesel vehicles are equipped with a Diesel Exhaust Fluid (DEF) injection / misting system for emission reduction, also known as 'AdBlue' or 'Bluetec', among others. OTC's DEF refractometer provides a quick and easy way of testing the condition of this fluid during servicing. Click here for more information.




  • Includes carry case, dropper, and cleaning cloth
  • Visually check condition of DEF fluid
  • Easy-to-use percentage display (ideal percentage 32.5%)