This is a simple, but elegant, rear lenscap for Minolta SR (also known as MC and MD) mount lenses. These lenses were used on Minolta SLRs from 1958 on, but were essentially orphaned after Minolta moved to an autofocus mount in 1985 because the SR flange-to-film distance is less than most other mounts can adapt without loss of infinity focus. However, they work great on mirrorless cameras such as the Sony A7/A7R. You can still buy rear caps, but this one has a bit more style.
Well, this isn't quite an easy print. The thing that needs to be precise is the ramp that holds the cap on the lens, but printing that face-up means that the back of the cap is printed as unsupported spans. Printed without supports, there will be poorly-bonded strands, but they'll be on the inside, so they don't really matter.
I printed it in PLA at 0.25mm and 25-40% fill. Blue and white were Minolta's packaging colors, but obviously any color(s) would work. I used a toothpick to place white paint in the embossed lettering; it isn't great, but it is readable enough.
The "minolta" text is simply a way to identify the mount; this lenscap is in no way a Minolta product. (The two STL files differ only in how much the text is rotated; they both work, but one or the other lines up text better with the top of the lens, depending on minor variations in lens flange thickness -- official lens caps don't line-up printing on them consistently either.) Although the mount is technically called SR, and MC and MD are just lens designations adding features to SR, I figured it would be easiest to identify the mount by a pre-1981-style lowercase "minolta" as seen on the SRT and other SR-mount cameras. Later Minolta cameras used an uppercase logo which most people would associate with the incompatible AF mount (which is now also known as Sony A mount).