Hydraulically Operated Rotating Cylinders are versatile with through port and stroke detection features, as well as very durable due to non-rotating port connections. The Cylinders have speed rotation up to 7000 rpm on all bore sizes with future engineering for higher speeds. The Cylinders are individually balanced that enhances speed operation in vertical, horizontal and inverted applications for smooth quiet machine operation and improved part finishes. The Cylinders provide maximum protection and have internal check valves trap operating pressure in cylinder in case of power or hydraulic system failure. The Cylinders have efficient and compact design that allows operation in restricted areas that makes it ideal for vertical applications where spindle-to-floor clearance is limited. The Hydraulically Operated Rotating Cylinders can be used in a multitude of environments.