Three-Piece Hand Tap Set, Tap Thread Size 9/16 In.-18, High Speed Steel, Bright (Uncoated), Thread Standard UNF, Thread Length 1 21/32 in, Overall Length 3 19/32 in, 75 Percent Thread Drill Size 12.90 mm, Thread Limit H3, Class of Fit 3B, Thread Direction Right Hand, Number of Flutes 4