Skimmer Rings have come in a variety of sizes.  The three here are all 4" or less in diameter.  The Hunt's Ketchring was made by Republic Tool and Mfg. Corp. in Los Angeles.  The 7-11, Wendy's, Chuck E Cheese and Weet-Bix  ring examples are from the Fast Food and Cereal Minis sections. The WIOQ Ring is from the same mold family as the Wendy's Fun Flyer and released in 1986.