This is a holder for trumpet mouthpieces. This holder should clip on to your standard metal music stand and let you quickly swap between your mouthpieces mid performance. This is especially useful if you are sitting and don't want to become part of the percussion mid-concert from a mouthpiece slipping from your pocket onto the floor.
Disclaimer: I am not responsible for dropped mouthpieces. Make sure your rack is secured well and be mindful when mouthpieces are attached to your music stand. If it seems sketchy to use, don't use it and be safe than sorry.
This part prints vertically so the only overhangs are inside the holes themselves so minimal to no support is required depending on your print settings.
This thing is available in two different models, a 3 hole and a 2 hole. The 3 hole is recommended even if you don't need them as the extra width provides extra stability.