Simple drying hanger/rack for Retainers or Invisalign so that they can hang to dry after cleaning or when not in use. 

I used a 1/4" ID x 3/8" OD Food Grade Silicone tubing to slip over the hanger post so the retainers wouldn't sit directly on top of the 3D print. Cut the piece of tubing to 49-50mm or just slip it over post and cut it flush to the end with a utility knife. Bambu offers this as well in the Makers supply. 

The curves on the rear of the base are for aesthetics but I should've went without them as it would've printed cleaner. I mostly care about the function though so didn't care to go back and change it and it is not noticeable unless you pick it up to look at it. The backside is flat so you can print it laying down, No supports needed but may help the quality on the rear of the base, or you may experiment with layer heights to get a better finish if you desire. I used a 3 mm brim for stability. If there is interest I can change it to square that off.