Based on the G.I. Joe Whirl Wind and scaled up to fit most 1/12 figure lines. The Barrels are designed to spin like the original toy. They are set up to print in place both for FDM and REsin printers, there is a .3mm clerance built into the part, so that is what you will need to be calibrated to work with in your printer. Some glue is required. and the wheels are setup to use a 1/4 inch rod as an Axel.