An image of two tanks of refrigerant that are both commonly used within the residential hvac equipment. The green tank is that of r-22, which was phased out due to its ozone depleting characteristics. The pink one in the front, is r-410a refrigerant, which was the new non-harmful solution to r-22 refrigerant, however it is not considered to be a 'drop-in' refrigerant or a compatible refrigerant that can be used in the same equipment. R-410a cannot be used in r-22 equipment.