... ,4mm,4.5mm,5mm,6mm,7mm,8mm,9mm,10mm,11mm,12mm,13mm,14mm,15mm,16mm,17mm,18mm,19mm,20mm,21mm,22mm ... tool accessories.Production includes milling chuck series,CNC tool series,collet series,boring heads series,etc.Sales covering the USA,Germany ... be happy to give you details. DIN6499B Standard of ER40 Collet