Nitrogen Cylinder 5 lbs. - EMPTYThis 5 lb. cylinder is rated to work with nitrogen. Unlike CO2 cylinders, the valve has a female connection, which mates with nitrogen regulators. You may also fill nitrogen cylinders with "beer gas", a blend of CO2 and nitrogen. Shipped Empty. Note: Cylinder may have cosmetic blemishes. Requires a Nitrogen Regulator. Proposition 65 Warning for California Consumers: This product contains chemicals known to the State of California to cause cancer and