OT5025 DEF Refractometer

The 5025 refractometer is a portable, precision, optical instrument used for measuring the DEF concentration. When a liquid sample is placed on the prism, the light passing through it is bent. The more concentrated the liquid, the more the light will bend. It contains a reticle, or scale, that is enlarged through the eyepiece to measure this light; and the values on the scale have been established to evaluate the DEF condition. According to Adamson, simply place a small liquid DEF sample on the refractometer prism, look through the eyepiece, and read the scale, which has been specifically calibrated for DEF.