This holder is best used for holding drills, reamers, taps, etc., without tailstock mounting. It uses a drill chuck mounted directly to a quick change holder. This holder is supplied with a drill-chuck. Fits industry standard tool posts. Thru hardened, ion-nitrided, and black oxide coated. CNC precision ground and qualified for accuracy and super precise tool change repeatability within 0.0001". Applicable for center drilling, precision drilling, precision reaming, tapping.