Transcritical CO2 Booster display case refrigeration systems are an HFC-free refrigeration alternative that utilizes carbon dioxide as the only refrigerant in the system. Supermarkets, grocery stores, small format and large format food retailers can take advantage of the inherent benefits of CO2 and combine them with those of other Second Nature systems – reducing direct refrigerant emissions to the lowest level possible. This paper outlines the details about this system and its benefits