This is a 16 piece High Speed Steel Metric drill bit set. Sizes are in mm: 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.6, 2.7, 2.8, 2.9, and 3.0. These will fit in Dremel/Rotary Tools.