For use on right angle grinders.  They all feature a 5/8"-11 hub. Gold is our most popular & economical wheel.  For general purpose use, fast cutting.  Orange wheels designed for aluminum, aluminum alloys & cupro nickel weldment.  Provides extremely cool cutting quality & will not load.  Black Topper is a dished wheel (saucer shaped) whose special design results in faster cutting & increased grinding efficiency, extremely long life.