This space-age Paper Mate lady capri (1957–1963) slim mini-pen is described as "precision engineered from ... shining chromium and vivid jewel-tone butyrates." (Butyrates?)
I found it at the Thrift Store, sorting through a soft paper bag of old stationery, some of it unusable, that also included a half-used box of these bluebird mail delivery cards, by American Greetings.
Unfortunately the pen doesn't work, and you can't get the original "Piggy-Back Detergent Action" ink refills anymore.
I did find this do-it yourself tip but I don't think I'm motivated enough to take these steps:
I found some cut-to-size Fisher Space Pen refills on ebay. For the Lady Capri, the indicated cut points were too large, so I used a fine saw to cut the refill, and then I removed excess ink with a toothpick to avoid leakage into the pen.