Welding sockets GN 7490 are used to attach threaded connections to containers, tanks or hydraulic cylinders via welding. Filling and draining screw plugs as well as aeration and venting elements and oil level sight glasses can then be easily installed by screwing them in. The flat surfaces are machined and can be used as sealing surfaces in connection with a suitable sealing element. The sufficiently dimensioned walls prevent deformation or burn-through during welding. Type B (with collar) is used if exact positioning within the mounting bore or a low installed height is desired.