4 Piece, Forstner, High Speed Steel Bit Set, Sharp Center Spur Accurately Locates The Center Of Your Hole, Use For Drilling Flat Bottom Holes, Pocket Holes Or Overlapping Holes, Set Includes 1 Each: 1" (Cut Diameter: 1", Overall Length: 3-1/2", Shank Diameter: 3/8"), 3/4" (Cut Diameter: 3/4", Overall Length: 3-1/2", Shank Diameter: 3/8", 1/2" Cut Diameter: 1/2", Overall Length: 3-1/2", Shank Diameter: 5/16" & 1/4" Cut Diameter: 1/4", Overall Length: 3-1/2", Shank Diameter: 1/4".