I wanted something I could easily break down smaller and take with me to shows. This model has both a larger square base for taller stacks or a smaller circle base for minis or small stacks. There is a bottom shaft labeled. and the center shaft is only needed if going three tiers or higher. The top shaft has the shorter tab for the top cap. Two variations of the top cap, one solid, and one with a slit as photoed for signs or label. There are also several tray variant between open up to 4 section trays. These spin freely with no added parts or equipment. Mine was printed in petg. This model is for personal use only for Commercial use it is available on Cults.