Urea -Adblue -DEF Refractometer Tester is a portable, precision, optical instrument utilized for measuring the Diesel Exhaust Fluid (DEF) concentration. Urea -Adblue -DEF Refractometer Tester contains a reticle, or scale, that is enlarged through the eyepiece to measure this light. Its accuracy is only as reliable as the cleanliness of the sample well. We are giving this tester in diverse specifications to choose from. Customers can purchase this tester at affordable price from us.