1/4" Diamond Tip Drill Bit (Tiled Walls) - GrabBars.com
Diamond Core Drill for Blind Holes Stone Worm cylindrical stem
DrillGlass 3/8" Diamond Core Drill Bits (3 Pack) 1 for Drilling Cutting Holes in Glass, Tile Ceramics, Porcelain and Stone ! Fits Your Drill or Drill Press (38DHS-3) - Amazon.com
Diamond Drills - specializzati in utensili diamantati per la lavorazione del vetro