This is a collar that lets you insert a 0.5 mL tube into a 1.5 mL tube. A set of 24 pieces prints in about 1 hour (60 mm/s, 0.40 mm nozzle).

The usual way to centrifuge a 0.5 mL tube is to nest it inside a 1.5 mL tube, but I sometimes had catastrophic failures when centrifuging samples for long periods at high speeds; the smaller tube would twist inside the larger tube, its rim would get wedged, and then it (and the tube's cap) would rip off entirely. The rest would shoot through the bottom of the 1.5 mL tube, leaving me with complete sample loss and a mess to clean up. By supporting the smaller tube's rim more evenly, this adapter makes this kind of failure less likely. And if it does happen, there's a chance that your sample will be caught by the 1.5 mL tube and you won't lose it entirely.

I have successfully tested this in PLA, spinning full tubes at 15,000 RPM (around 21,100 RCF) for 10 minutes at a time without damage to the tubes or delamination of the adapters. You should test your own tubes and prints to make sure that they can withstand centrifugation at the forces, periods, and temperatures you need, before you risk samples. This collar cannot help you if you use weak, low-quality tubes!