In anticipation of the Pentax 17 camera, I remixed the 35mm slide holder for a vertical 17x24mm image
** A "SLIM" version is also offered which shaves 0.15mm of the original so it doesnt get stuck in carrousel projectors as noted by an early adopter.
Remix of https://www.thingiverse.com/thing:3215812
Please see the instruction in that thing