The Refrigerant Discriminator provides a fast, easy, and accurate way to determine the type and purity of your refrigerant. This instrument utilizes an infrared comparison and chemical fuel cell technology to determine the purity and contamination levels of R12 and R134a, as well as the content of the air. The sample gas enters the instrument's sensing device through the sampling tube, and the purity of the refrigerant, the conditions under which it can pass and the amount of contamination are displayed digitally in the instrument. A sample is judged to pass when it is 98% or more pure than a single refrigerant (R12 or R134a). The instrument also provides identification for R22, hydrocarbons or other refrigerants commonly used in blending, and the filter is designed to protect and improve the accuracy of the digital display in the instrument.