All of the gas containers Rotopax manufactures for the United States are molded using their patented three layer design. This state of the art molding technique exceeds the EPA (Environmental Protection Agency) and CARB (California Air and Research Board) requirements. Making Rotopax the only Rotational molded EPA and CARB compliant container on the market. The Rotopax Gas containers are offered in various sizes depending on your needs. 1, 1.75, 2, 3, and 4 gallon. Remember to vent the pax regularly.