J.H. Williams Tool Group, a unit of Snap-on Industrial (Kenosha, WI), offers single-acting lock nut cylinders in diameter sizes from 2 to 12". Units are designed to support loads for extended periods without hydraulic pressure; an overflow port prevents cylinders from travel. Units are 10,000 psi/700 bar with weight capacity ranges to 100 tons. Lightweight aluminum cylinders in diameters from 2 to 12" and double-acting cylinders from 6 to 20" also are available. The double-acting cylinders include rod wipers to seal dirt and other contaminants.