A ferrule (120) for coupling a tube (112) to a fitting body (114) includes an outer cam surface (124) for bearing against the fitting body or another ferrule; an inner surface (126) defining a central bore (128) extending through a length of a body of the ferrule along a longitudinal direction from a bite edge (138) to a nut end (129); a recess surface (134) defining a counter bore extending from a bite end (137) to the bite edge (138), the bite edge (138) thereby recessed from the bite end (137).