The Z grill was an embossed pattern intended to make a stamp absorb cancelling ink and discourage reuse. Its horizontal ridges distinguish it from the other grill patterns. This one-cent example entered Benjamin K. Miller’s collection and is held in the New York Public Library’s Miller collection. It is one of two recorded one-cent Z Grills, rather than the other copy associated with William H. Gross. The National Postal Museum announced that the Miller collection would return to public display on 27 May 2006. The exhibition brought the two recorded examples together temporarily.