Copper Filter Driers are made of good quality copper pipes and copper thread backstops, and top-grade molecular sieves. It’s adaptive to R12, R134a, R502, R600 and refrigerators using capillary tubes for throttling, freezers and middle and small scale all-closed refrigeration systems. It’s used to absorb remaining moisture in the system and remaining impurities and foreign matters in the filter system, in order to avoid “ice jam” and “dunghill jam” in the systems.