These Minis were made in Canada for Nabisco Shreddies as a tie-in to the release of the Walt Disney movie, Tron.  The Minis have a 1981 date on the back, which also says "Canada", but they were released in 1982, only in Canada.  They are 3.5" diameter with a depressed center similar to the molds similar to those used by McDonald's, General Mills, and others.  They were made in 4 colors: red, blue, yellow, and green, and with 4 characters: Tron, Flynn, Sark, and Yori.