HFA - Single Acting Failsafe Lock Ring Aluminum CylindersCapacities from 35 to 121 tons. Stroke lengths from 2. 01 to 12. 02 inches. Working pressure 10,000 psi. Lightweight aluminum cylinders for applications where weight and portability are of prime importance. Single acting, spring assisted return. Mechanical lock ring feature allows for load holding for extended periods. Hard anodized piston rod and cylinder for corrosion resistance and increased durability. Low friction bearing surfaces. Anti extrusion