Thank you Spotmatic! Yes I agree, 3D printed caps are often not ideal, they tend to break at the weakest points (and small brocken plastic parts don't go well with camera equipment;)).

Sorry to hear that. Thanks for the valuable input. It was made when I just picked up 3D printing and therefore it's not the best designed cap I've made. These days, I avoid 3D printed material as caps. Instead, I use soft white caps that Pentax have made. Source (see about the LX): https://harrowtechnical.co.uk/camera-faults/

Sorry "Spotmatic" but this cap does not fit on any of my Pentax K mount cameras. The cap can not be locked because the hinges are not placed the right way.