Permanently attached ferrule allow fittings for use in high-pressure applications. As the fitting is tightened, the resistance of the cap increases until the correct torque is reached. The fitting can spin freely from tubing, preventing tubing from twisting. A recess in the fitting houses the ferrule, allowing maximum thread engagement with the port. Select fittings from acetal, polycarbonate (PC), or PEEK™ material of construction. PEEK fittings are compact in design and provide excellent chemical resistance.

Both Type P and Type S ferrules fits permanently onto the outside of semi-rigid tubing. Type P system uses a one-piece ferrule with only the inner PTFE sealing face in the fluid path. Type S system uses a two-piece ferrule made up of an inner PEEK or ETFE sealing surface surrounded by a stainless steel lock ring with only the inner portion in the fluid path.