I may be reading too much into the post by sdemirjian, but the rubber doesn't have to be destroyed in the process of taking it off. I have removed/replaced mine quite a few times. I too have the right-angle finder and I have made it a habit, when screwing the normal eyepiece back on, to barely tighten it. (I do the same with the magnifying eyepiece.) The lever that locks it in place will keep it from unscrewing. I've not lost one yet.