Though R-134a is a HFC refrigerant which has no influence on Ozone Layer, R-134a affects on Global Warming. Recently in several countries, there are some regulations to Global Warming Potential, which is called GWP. GWP is the index of influence on Global Warming caused by refrigerants. The GWP of R-134a is regulated in some countries. Therefore, the automotive industry is looking for new low GWP refrigerants and the oil which matches to new low GWP refrigerants. Idemitsu developed new PAG which is suitable for not only R-134a but also new low GWP refrigerants.