RRH-Series Hollow Plunger Hydraulic Cylinders are ideal for tensioning, testing, pulling, and lifting applications. The hollow bore, base threaded holes and collar thread allow attachments that enable the cylinder to deliver both pull and push forces. RRH double-acting center-hole hydraulic cylinders feature two connection ports to provide hydraulic flow to both advance and retract the plunger. This provides a more controlled retraction than single-acting cylinders. Cylinders in the RRH-Series are constructed from high-alloy steel and finished with a baked enamel exterior coating. Collar threads and base holes for easy fixturing are provided as standard. Enerpac has designed and manufactured 10,000 psi (700 bar) high-pressure hydraulic cylinders for many decades. We use only the highest quality materials to ensure they can withstand the most demanding applications. All RRH cylinders meet the safety standards required for high-pressure hydraulic tools. Relief valves prevent damage in case of over-pressurization Baked enamel finish for increased corrosion resistance Double-acting operation for fast retraction Nickel-plated, floating center tube increases product life Hollow plunger allows for both pull and push forces CR-400 couplers and dust caps included on all models Plunger wiper reduces contamination, extending cylinder life