A plumbing connector and method of connection including: a fitting having external threads on at least the first end; a tube having a first end inserted into the first end of the fitting; and an annular gasket, a compression ring, a lock ring, and a nut coaxial with and surrounding the outer diameter of the tube. The nut has internal threads adapted to engage the external threads of the fitting and is adapted to contain the gasket, the compression ring, and the lock ring upon threading of the nut onto the fitting. Upon threading and tightening of the nut onto the fitting, the gasket is compressed, an inner edge of the lock ring bitingly engages the outer diameter of the tube, and the gasket forms a seal with at least the first end of the fitting, the outer diameter of the tube, and an outer edge of the lock ring.