R32 is a low GWP "hydrofluorocarbon" (HFC). It is an A2L Refrigerant meaning it is mildly flammable.
It is used in small split Air Conditioning systems where the charge size complies with the requirements of EN378.
It is not a retrofit option for other AC systems running on other refrigerants. It is also used as a component in both HFC and HFO blends.