iDichroic Crafter's Best Stained Glass Grinder Head Bits Set- 4 Sizes Diamond on Brass Core 4 Deluxe Crafter's Best Stained glass grinder heads 1", 3/4", 1/8",1/4". ALL Standard grit. Diamond abrasive bonding surface is double plated for strength and long life Superior quality and low cost means you get a high value Warning These Grinder Bits will not fit the Powermax or Glastar All-Star Grinders