This is interesting: Melissa claims that the keycaps molds they use are "40 years old", but SigPlast website says, "Established in 1995, Signature Plastics". So, where did their molds come from? I was assuming, primarily from front side sprue marks and very thin plastic, that the WYSE50 keyboard keycaps are from SigPlast's molds, but it must have been another company that originally made them (and SP bought the molds?). Now that I look more closely, I see that the Wyse50 keycaps have two "fins" underneath that support the sides and the Cherry MX mounting post, while the few SigPlast keycaps that I have managed to get my hands on do not have these "fins". hrmmm....