Interestingly, I am told I have an upgraded 300 rpm motor, that came with my Aries III, but the motor is 4.5 inches tall from the bottom of its rubber feet to the top of the stainless steel housing and my Aries III plinth is 4 inches tall from the top of the plinth to the bottom of the cones. I have noticed this upgraded motor has a 3/8 inch metal strip bottom between the stainless steel housing and the rubber feet. If true, that is how you can identify it. If its 4.5 inches tall, some will have to make adjustments to their table with spacers, pucks, etc. for it to fit correctly from a height perspective with the table.