When selecting a head for a your Coats tire changer, reference the second picture shown on this page. The stub sticking out of the shaft that holds the head will be either tapered (smaller on the bottom than the top) or it will not be.
Mount head for Low Profile Tire fits Coats®* Tire Changer Mount Demount Head
Nylon Duckhead for Low Profile Tires Coats Tire Changer
Low Profile Plastic Gray Nylon Mount/Demount Head Kit Fit for Coats 8184432
2 Pack TC184432 8184432 Low Profile Nylon Mount/Demount Head Kit Fit for Coats
TMR High Spoke M/D Head w/ Low Profile for Coats - USA MADE, Gray - HEAD ONLY