R-406A is a refrigerant

Refrigerant

A refrigerant is a substance used in a heat cycle usually including, for enhanced efficiency, a reversible phase change from a liquid to a gas. Traditionally, fluorocarbons, especially chlorofluorocarbons, were used as refrigerants, but they are being phased out because of their ozone depletion...

 invented by George H Goble. It is a mixture of three components chlorodifluoromethane

Chlorodifluoromethane

Chlorodifluoromethane or difluoromonochloromethane is a hydrochlorofluorocarbon . This colorless gas is better known as HCFC-22, or R-22. It was once commonly used as a propellant and in air conditioning applications...

 (R-22), isobutane

Isobutane

Isobutane, also known as methylpropane, is an isomer of butane. It is the simplest alkane with a tertiary carbon. Concerns with depletion of the ozone layer by freon gases have led to increased use of isobutane as a gas for refrigeration systems, especially in domestic refrigerators and freezers,...

 (R-600a) and chlorodifluoroethane (R-142b) in the ratio 55/4/41.

This refrigerant was designed as a drop-in replacement for R-12 which is compatible with the typical mineral oil lubricants used in R-12 systems. Since it is a zeotropic mixture, it has a range of boiling points which may increase the effectiveness of the heat transfer elements in refrigeration equipment.

Because it contains R-22, its future is limited due to eventual phase-out of this refrigerant.