Prototype -- The Proto or conventional types were styled to resemble the full size midgets of the day.  Typically, they had an open cockpit. 

Streamliner -- The Streamliners designs varied, but used an enclosed cabin or teardrop shape. These cars were the fastest.

Class B -- These are the larger size cars with .60 CID engines and lengths typically 15 – 22” (usually approx. 17”) and weighing 6 – 8 pounds

Class A – Also known as mite cars usually range from 9 – 14” in length and use .36 or less CID engines.