The invention relates to a pneumatic thread stretcher for a rapier weaving machine or a knitting machine, in which the air current deflection surface for deflecting the thread forms a seamless extension of the inner wall of the linear guide channel, through which the thread runs. A nonvolatile memory is disposed in a semiconductor integrated circuit device. The insertion ring has an insertion height and an angular outer ring wall which can be adapted to the inner wall of the cap, and which can be completely received in the hood between the inner hood wall and the pushbutton, and which diameter can be elastically varied section by section along the height of the insertion ring. In particular embodiments, communication handling may be affected by the determination of urgency.