This NxG carbon-wrapped quick-connect snap-change cylinder comes in grey and meets the NIOSH standard. It has a 4500 pounds per square inch pressure rating, 45 standard cubic feet air flow rate, and a 30-minute duration. The pre-filled cylinder measures 21 1/2 overall height x 5 11/25 inches diameter and is suitable for use with NxG2 self-contained breathing apparatus.