SummaryThis design allows to add a diopter and flip it in/out as needed. The basic idea has been motivated by Nauticam product, but I wanted a version I can print and also does not require screws.InstructionsThe design relies on a 72-67 step-down filter ring to provide the thread. I did not check different rings but I assume they are more or less of the same size. The design holds this ring very tightly, and so once it is inserted it is hard to remove it. The axle holding the frame is designed to be locked in by a small cable-tie. The design was printed with the PP3DP Up Plus printer. It requires support for various concave part. I am not sure how it works with other printers.