16pcs collet chuck holder mt3 m12 morse taper 3-20mm for lathe milling tools inner diameter3 /4 /5/6 /7/8 /9/10/12/13/14/15 /16 /18 /20mm. Collet must be assembled into the clamping nut before inserting into the chuck. Ease of operation and high quality work results. It is a precision collet for professionals and hobbyists demanding ease of operation and high quality work results.