These 6-piece 3/32 shank Swiss-made twist drills with electroplated diamond particles are the ultimate for drilling stones pearls glass or ceramics. Use with standard handpieces and a small amount of water as lubricant. All drills are medium-fine grit. Sizes included: 1.00mm, 1.30mm, 1.40mm, 1.60mm, 1.80mm and 2.10mm. (Sizes are approximate due to the nature of the coating).