Abstract: A fitting for attachment to a tube by swaging is disclosed. The fitting comprises a cylindrical sleeve having a tapered outer surface and an inner surface for receiving the tube. A cylindrical swaging ring having a tapered inner surface engages the tapered outer surface of the sleeve such that axial movement of the ring in a forward direction with respect to the sleeve causes the ring to apply a radial force to the sleeve to swage it to the tube. The swaging ring is comprised of a lightweight, high strength material, such as a composite material, having high tensile strength in a circumferential direction and a high modulus of elasticity, with relatively low density and low elongation properties. One preferred composite material comprises an epoxy resin matrix and a high strength graphite fiber. The swaging ring is locked onto the sleeve both before and after swaging by one or more protrusions on the outer surface of the sleeve which cooperatively engage an annular groove in the swaging ring.