FISCH Wave Cutter Forstner Bit Set, 16 Piece Set includes 12, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30, 35, 38, 40, 45, 50mm sizes All bits have an overall length of 90mm or 3-1/2" Bits require 25% less power due to ideal cutting geometries 3X holes of conventional forstner bits before sharpening Metric sizes are required for many hardware installations