This is a modular version of the planter pot booster, this version comes with a base and a booster, the booster locks into the base via 4 indexing lugs, these are pretty small and should be printed without supports at this scale or they will break. You will likely need to clean up the underside if there's any drooping. You can also just have them act as indexing pins instead.

Each section is 10mm in height, you can of course scale as needed.