Assortments of holesaws composed of popular sizes for the engineering industry, water and sanitation industry and electric installation industry.  21-Piece Kit contains:  16 holesaws (3/4, 7/8, 1, 1-1/8, 1-3/8, 1-1/2, 1-3/4, 2, 2-1/4, 2-1/2, 3, 3-1/4, 3-5/8, 3-3/4, 4-1/8, 4-3/4), 2 arbors and 3 pilot drills.