Abstract: A fitting of weldable thermoplastic material for connecting pipe elements or other fittings. The connection is obtained by welding by means of at least one heating element arranged at the surfaces of the members to be welded together. At least one weld indicator defined by a hollow space in the fitting is provided. The hollow space defines a first opening at the inner surface of the fitting and a second opening at the outer surface of the fitting. The first opening is covered by the heating element and the second opening defines a portion of reduced width, the portion of reduced width defining a retaining or cooling surface facing the interior of the hollow space. The second opening serves as an outlet opening for the melt. During welding, melt is conducted into the hollow space by the generated welding pressure. The melt solidifies when it reaches the retaining and cooling surface and only a small portion of the melt is conducted through the outlet opening for indicating a problem-free welding connection.