The Robinson Oil Thief is a proven design in oil thieves. The valve closure assembly is on the inside of the barrel, which makes a more compact unit at the bottom, allowing the thief to pass through an opening as small as 5 inches in diameter. The bottom casting has four legs which makes the thief a stable hydrometer cylinder. The top casting has a hanger for hanging the thief. It offers a single trip action, simple tension adjustment, simple seal and "O" ring replacement, adjustable graduated trip rod and viton seals. *Petcocks are not pre-installed and must be purchased separately.