Celestron large SCT threaded dust caps

From the original model: "Celestron 3.29"-16 threaded dust caps, male and female, for Celestron Schmidt-Cassegrain Telescopes (SCT).These threaded dust caps are useful for astronomy telescopes and adapters. This thread size is used on larger Celestron Schmidt-Cassegrain Telescopes (SCT). It is used on the EdgeHD 9.25" models (but not regular 9.25" models), and all larger Celestron SCTs. The thread size is 3.29"-16tpi which is very similar to the Meade 3.25"-16tpi threads for their large SCTs. They are very similar threads and are sometimes interchangeable.I print these dust caps out of PLA+ and have found that the threads print nicer in PLA+ vs PETG and that sometimes the threads are so fine that they don't fit as well with PETG. YMMV. Try enlarging/reducing the X/Y axes by 0.5% if they are too loose or tight." https://www.printables.com/model/745282-celestron-329-16-threaded-dust-caps-male-and-femal/