Abstract: A connecting piece into which is axially insertable in an insertion direction a profiled pipe member having parallel external grooves, where the connecting piece includes a connecting sleeve having an entry end for receiving the profiled pipe member and defines a cylindrical wall with plurality of apertures extending radially therethrough, and a clamping ring which is axially displaceable in the connecting sleeve and which is provided with a plurality of pressure fingers extending approximately parallel to a longitudinal axis of the sleeve and which are pivotable about a pivot region. In a fixing position each of the pressure fingers is positioned generally adjacent a respective one of the apertures, each pressure finger having a projecting nose part which is engagable into one of the external grooves of the profiled pipe member.