This is a KBC 3 inch NPT straight flute HSS taper reamer. Taper Pipe Reamers are intended for reaming holes to be tapped with American National Standard Taper Pipe Taps. Reamers are tapered 3/4 inch per foot. If you have any questions on this item or any of the other 100,000 items we list, Let us know. The part number on this one is 1-366-210