Recommended for use in high-speed air driven turbo handpieces with a range up to 80,000 RPM. The quality is excellent, with diamond particles electroplated onto surgical-grade stainless steel; the shanks are 1.6 mm (1/16″) in diameter, with an average length of 20 mm (3/4″). Set of 12; coarse grit. Includes a convenient storage/organizer pouch.