Most of the coil in the U.S. market is 4:1, but there are many other machines still in the market place which take 5:1 and 6mm pitches. The best way to tell which pitch coil you need to order is to punch an 11" binding edge and count the holes. The 5:1 pitch has 55 holes, the 4:1 has 43 or 44 holes and the 6mm has 45 or 46 holes.