PRG series oil filter can filtrate 99% of 3 micron grain but still have enough flow rate to maintain the flow pressure drop. PRG series oil filter has a very high capacity of filtration. It can return the cleanness POE oil and mineral oil bacR to the compressor. The clean oil not only can maRe sure the oil regulator worRing properly but also can reduce the abrasion of the compressor. PRG series oil filter actually can release changing oil for compressor that caused by suspend feculence during the worRing.