This "Beep" and "Boop" aluminum ring set is hand stamped with care, one letter at a time. At the end of each ring, there is a stamp of a robot. The rings are made out of Pure 1100 Aluminum, which is food safe and does not tarnish. They contain no Zinc or Magnesium which are often found in common aluminum and can cause skin reactions. This also means it doesnt contain the properties of other metals that might tarnish and/or turn your skin green. This ring is stamped on an aluminum blank and hand wrapped to fit your size. Please note that due to the nature of hand stamping, every item varies slightly from the photo.