Abstract: An inner member is telescopically mounted within an outer tubular member and is normally locked against telescopic sliding movement relative to the outer member by a coupling mounted for back and forth manual manipulation along the outside of the two telescoping members at the location where the two members are coupled together. Manual manipulation of the coupling in one direction unlocks the inner member to permit sliding movement thereof relative to the outer member and the coupling, so long as the coupling is urged manually in the one direction. When the coupling is released, it automatically locks the inner member against further sliding movement.