Steel hose ferrules are used with a barbed hose fitting and are crimped on large-diameter hydraulic hose presses to create a strong, permanent, tamper-resistant hose connection. G3S Sleeves will work with most barbed insets, while G3F ferrules are designed to interlock with G64 and G33C hose stems. Sizes refer to the inside diameter of the ferrule before crimping. Maximum retention strength is achieved using G3F ferrules with G64 and G33C stems. Short sleeves are generally suitable for attaching G33 style combination nipples. Longer sleeves are preferred for G65 cam-locks. In general, sleeves should be at least 1/4" shorter than the hose barb, and placed just ahead of the end of the barb on the fitting. For steam and for high pressure air service in larger sizes, G29C interlocking clamps should be used instead of steel sleeves.