Self align fittings series H, DL, L, LL has ten styles and five tube O.D's providing a wide range of fittings that will fit any application. Flared ridge ferrule prevents accidental loss of ferrule when inserting tubing into the fitting body. Hardened ridge ferrule prevents breakage of ferrule when tightening nut. Flared I.D. provides low flow resistance inside the fitting. The tube holding mechanism gives the strong feeling when inserting tube, and prevents tube from sliding when screwing in the tube.