Drill bits with a 3/32-inch diameter and a 1/4-inch hex shank featuring a black and gold (often described as gold oxide or titanium aluminum nitride) finish are designed for high-performance drilling. The gold coating typically indicates a surface treatment that reduces friction and increases heat resistance, while the hex shank allows for quick changes in impact drivers and prevents slipping in standard chucks. These bits often feature a 135° split point tip, which helps prevent "walking" (slipping off the target) and allows for self-centering on hard materials like stainless steel and iron.

QEP's Xtreme Series 1-1/2" (38mm) Diamond Milling Cone is designed to enlarge, shape and round-bevel existing holes in porcelain, hard ceramic, granite and marble. It is manufactured with superior brazed diamond bonding for greater durability and faster, smooth cuts. It can be used for polishing, stone carving, hollow tangent, and trimming. It works with all standard grinders, no adaptor necessary.