These dust plugs are thinner and more flexible than I was expecting. I suppose they are fine if you just want to push the plug into an opening, but I needed a stiffer more solid plug that would be gripped when I tightened a focuser or diagonal’s thumbscrew. These just squish in while tightening the thumbscrew and easily pop out of the opening.

Everything fit perfect.

I purchased this dust plug for my TPO 12" f/4 Imaging Newtonian telescope, this OTA only comes with a 1.25" dust plug. I don´t know why Optcorp does not include this one in this telescope ... It is necessary to buy it for those who wear eyepieces or accessories of 2 inches in diameter. I recommend that when buying this OTA, immediately buy this item. Fortunately, Optcorp has it as an option to buy