This is a tray where you can pour the parts back into a baggie or storage container. I have printed several and use them all the time.  They are stackable and print with NO SUPPORTS required.

This part is also optimized for 0.4 mm print nozzles. The walls are an integer multiple of 0.4 mm and print exactly with 2 shells. These optimizations cut printing time in half!

The base is designed to print at 0.28 mm layer height (instead of 0.3 mm). Many 3D printer motors have a 0.04 mm z-axis stepper resolution. They can move to other positions, but the motor is holding between steps and is not stable. When using an integer multiple of 0.04 mm for z-axis layer height, the layers are much cleaner and have better layer-to-layer adhesion.