Each is 7/8”. First without backpaper shows product canister of “Egg Baking Powder” and with flanking text “Pan-American Exposition 1901.” Four pinpoint gray dots on rim edge barely show. Second is first we’ve seen button showing North and South American Continents with lines depicting the world globe. Text is “Pan-American Buffalo 1901.” Design has tiny blue circle on the United States designating the location of Buffalo. Reverse has W&H paper. NM displaying Mint.