Abstract: A cleaning device for a well bore which is adapted to be connected to a drill string for insertion into the well bore and through which cleaning fluid is pumped, comprises an elongated outer sleeve having an axially extending through bore therein and at least one port in the side wall of the outer sleeve, each of which ports is axially spaced along the outer sleeve. An elongated inner sleeve having, an axially extending through bore therein is coaxial with and axially slidable within the outer sleeve. An annular seating collar is located within the through bore in the inner sleeve and at least one port is provided in the side of the inner sleeve. The ports are axially spaced along the inner sleeve. Pressure sensitive stops means serve to retain the inner sleeve in place within the outer sleeve at each of a plurality of predetermined axially spaced positions in turn.