If you are currently using a channel style frame system on your screen decks, you may have wondered how the twenty-three millimeter hole size became the universal standard. Well, the story goes that, in the early 1970's, Manfred Freissle had begun development on his revolutionary concept for a modular synthetic screen system. His work included designing a frame on which to attach the screen panels. He experimented with materials already laying around, which included pieces of channel stock and one of the drill bits used in his wire cloth business. The size of the drill bit? Twenty-three millimeters, and the rest is history.