Lance for receiving sensor or sampler for metal melts

A lance has a top part and a bottom part for arrangement on the sensor or sampler. The top and bottom parts are detachably connected to each other by a plug-in coupling. The plug-in coupling has two coupling parts, one arranged on the top part and the other arranged on the bottom part of the lance, that can be inserted one in the other in the longitudinal direction of the lance. One coupling part has an opening extending from its front face in the longitudinal direction of the lance and an extension formed in the peripheral direction of the coupling part. The other coupling part has a raised portion that engages the extension. A blocking device, movable in the longitudinal direction of the lance, is arranged on the top or bottom part A catch element of the blocking device is arranged at least partially between the raised portion and the opening.