An elongate container includes a cylindrical chamber having an opening at one end of the container. A collar is affixed to the elongate container, and a threaded rod is axially disposed within the cylindrical chamber and coupled to the collar. The collar is adapted to rotate the threaded rod relative to the elongate container. A piston is disposed within the cylindrical chamber and is threadingly engaged with the threaded rod. The piston includes a sealing ring adapted to circumferentially seal against an inner wall of the cylindrical chamber and at least two axially aligned ribs. The ribs are disposed on a side of the piston and seated against the inner wall of the cylindrical chamber. With this arrangement, rotation of the threaded rod causes translation of the piston in the axial direction.