Each blade is carefully polished after being hardened, resulting in an unprecedentedly smooth piercing of leather. *Pro-punches are manufactured with the assumption that they will be used to punch holes in leather that is 2.0mm thick or more. Using them on leather thinner than 2.0mm or soft, thin leather such as chrome-tanned leather may worsen the blade's alignment, preventing holes from being punched. Size: Stitch pitch: 3mm Used only a few times, with no chipping or other damage, and in relatively clean condition.