Diamomd Coated Core Drill 6.5mm
They are perfect for cutting holes in hard non-metallic materials such as stone, glass and ceramics without chipping or cracking. These stainless steel core drills have diamond particles electroplated on them in a medium/fine grit (120-140grit).
Shanks are 1/8" (3.18mm).
These diamond drills are a premium/professional grade that are manufactured to last many times longer than cheaper diamond points.
Remember to always use water or a diamond lubricant when using diamond instruments of any kind.