This is a set of 5 identical professional quality CNC cutting tools, individually packaged and made from solid Tungsten Carbide (TC) with 3 /4" double flutes and 1/4" square flat head. The overall length of the bit is 2.5" CNC routers are designed for steel and have a titanium nitride (TiN) finish to increase heat resistance and reduce wear to reduce. I found that I could use this for plunge cutting with my router, but it's actually designed for cutting metal on a standard CNC machine, not for cutting unmarked wood. I'll write on them with a marker to add to my bits to give me a chance I'll process the steel when I get the gear for that purpose. I highly recommend this Carbide Square End Mill for CNC Milling Tools for Alloy Steels/Hardened Metals - 2 Flute - 5pcs. I hope you found the information and my review helpful.