Abstract: An improvement in a light waveguide plug which enables compensating for offsets due to tolerances in the parts characterized by a plug pin having an internal clamp seat for receiving a swivel member. The swivel member has a projection or stem with a portion extending out of a free end of the plug pin. The end sticking out of the plug pin has the waveguide surface flush with the surface of the end and that surface has a crown or slightly convex surface. The swivel member can be moved so that the offset can be corrected up to approximately 4.mu.. Thus, the end of the optical fibers exit and entrance surface can be concentrically disposed to lie on the axis of the waveguide plug.