How can I tell the difference between an S1 and a S2 Burr?

How can I tell the difference between an S1 and a S2 Burr?

The difference in the burrs as you can see in the image is that the S2 burr upper teeth (cutting surface) (photo on the right), is flatter than the S1 burr which has sharper pointed upper teeth (photo on the left). This variation in the cutting surface of the burrs is what creates the grind differences on the fine to coarse continuum.