Abstract: A flareless fitting includes a coupling body, a coupling nut and a ferrule. A tube is inserted so that it may extend axially inwardly a variable insertion length beyond the ferrule, through the length of a counterbore which is slip fit about the tube. Tightening of the coupling nut and the tapered arrangement causes the ferrule to be sealed between the tube outer wall and the internal cylindrical surface of the coupling body. Specifically, a single tube fitting system is provided which offers substantial tube penetration, or shallow tube penetration, without using two different kinds of fittings.