The "Blue and Improved" The Original Line® Rod Lock cylinder feature permanent grease lubrication. Design enhancements have more than doubled the anticipated service life of this cylinder, featuring a biased normally closed clamp on the piston rod that holds the rod in position when air pressure is not present. Bore sizes:  3/4", 1-1/16", 1-1/2", 2", 2-1/2", 3"The rod lock design is not a safety deviceHard chrome plated stainless steel piston rod50 PSI minimum required to release locking mechanismBlue and Improved design doubles previous cylinder lifePermanent grease lubricant requires no additional lubrication during serviceEngineering SpecificationsPressure Rating: 50 PSI minimum (to actuate lockpiston),125 PSI maximumTemperature Range:Buna N seals: -20° F (29° C) to 200° F (90° C)Fluoroelastomer seals for high temperatures (up to 400°F) availableMagnetic piston option: max. operating temp. is 185° FMaterials:Rod: Hard chrome plated stainless steelBody: 304 stainless steelEnd Caps: AluminumRod Lock Cap: Anodized aluminumRod & Pivot Bushings: Sintered bronze