High quality 5lb aluminum CO2 cylinder. The perfect size for almost all planted tanks. Dimensions: 5 1/4" D x 18" H CO2 Capacity: 5 lb Sherwood USA Valve Made of high strength 6061-T6 Aluminum alloy Tested in excess of 100,000 cycles at service pressure. Minimum burst pressure tested to 2.5 times service pressure without failure. Corrosion resistant interior and exterior. Manufactured in accordance with US Department of Transportation (DOT) 3AL. Manufactured in accordance with Transport Canada (TC) 3ALM requirements.