Apollo metal gobos are made from an 8 mil stainless steel with a high quantity of nickel and chromium that provide longer life and image quality. The majority of alternative products on the market are made from a 5 mil stainless steel comprised of a large amount of carbon steel that begins to oxidize (rust) and breakdown in a shorter period of time. If a magnet sticks to the pattern, it is mainly carbon steel - which means it is not an Apollo pattern.