Series H, DL, L, LL ferrule fittings are available in ten models and 5 tube outside diameters, providing a wide range of fittings for all types of applications. A clamping ring prevents unintentional loss of the ring when inserting the tube into the fitting body. The robustness of the ring prevents it from breaking when the nut is tightened. The tube guide offers low flow resistance inside the fitting. The tube-holding mechanism offers resistance when inserting the tube and prevents it from slipping when screwed in.