Henry’s high-efficiency, TriTex filter system provides enhanced filtration, meaning what goes in, stays in. Not sure which size is right for your Henry or Hetty? The label under the handle on Henry, Hetty or Harry (or on the rear of your machine for James, Charles & George) will contain the model number. The 12″ Filter Kit will fit machines including “180,” “200,” “240” or “370” in their number, the 11″ Filter Kit will fit 160 machines. Please note separate option for Henry Allergy owners.