Our new stainless steel pricking irons, also known as thonging chisels, help you to keep your hand sewing/stitching lines straight.  We have these available in the sizes shown in the image:  10 holes, 6 holes, 4 holes, 2 holes, or 1 hole, and the spacing is 4mm.  The 10 hole iron is $14, 6 hole is $12, 4 hole is $10, 2 Hole is $8, and the single hole model is $6, and USA shipping, of course, as one would expect, is free.