These heavy-duty PTFE agitators impart maximum energy and are offset at the bottom to accomodate slurries. 10mm agitators fit drilled type or knob type 8068, 8071 & 8075 shafts. 19mm agitators fit drilled type or knob type 8076, 8078 & 8079 shafts. 28mm agitators fit 8080 drilled shafts.