In my review of the 2" pulley, I stated that the key slot was undersized. In this pulley, the key slot was exactly 3/16" as it is supposed to be. Unfortunately, the key I was using was oversized, so I had to file the key again. Cosmetically, this pulley is designed to have a counterweight for the extra metal required for the set screw, my old one had a larger/heavier ring around the shaft to act as the counterweight. This is just a design difference and does not affect the operation of the pulley. I am satisfied with this pulley.