Precise flange thickness and reduce nose diameter allow this tool holder to be used on NMTB machine with Quick Change spindle / Nose diameter 1.25" / All critical surfaces precision ground / Made from alloy steel hardened to 55 - 56rc / Runout is less than .00019" at collet face and each holder comes with a manufactures runout inspection report / Each holder undergoes a sub-zero cryogenic treatment which prevents deformation over time /