These are a few additional pieces designed to work with Rocketship Game's hexagonal 'Deployable Containers' which are available on DriveThruRPG here: https://www.drivethrurpg.com/product/216929/Deployable-Cargo-3D-Printable-SciFi-Containers

The joiner is a simple hexagonal ring designed to let you glue two printed, open-ended containers end-to-end. It's slightly undersized so scale it when you print. 102% works for me, but you may have to experiment.

There are also two open 'cage' style end variants, one with a snap-in moveable door, and the other a fixed cage. Combine these with the open-ended container to transport your 28mm dangerous lifeforms or prisoners.

Another end cap variant adds two airconditioning or refrigeration units to a container.

There's a half-hex support stand. This lets you stack a set of these containers horizontally in a beehive style formation.