Made of long lasting High Speed Steel (HSS). The tips are designed to prevent chipping of pearls Each pearl drill is double-sided with the bit meeting in the center. Use for full-drilling and half-drilling. For full-drilling a hole in pearls for necklaces, earrings and bracelets. For Half-drilling to realize your designs for earrings, rings, pendants, broaches and other designs. Use for drilling holes into Freshwater, Cultured to Akoya and Tahitian Pearls. Sold Individually.