A Tungsten Carbide Tipped annular cutter is the way to go for cutting mild steel and difficult to cut material such as stainless steel and bisalloy. These particular Annular cutters come fitted with a universal shank therefore can be used in magnetic based drills such as: Alfra , Hougen , Jancy , Euroboor , BDS , Ruko. Tungsten carbide is a chemical compound containing equal parts of tungsten and carbon atoms. It starts off life as a fine gray powder and then can be pressed into different shapes such as a black that can then be ground to the correct geometry and braised onto an annular cutter etc. Becuase tungsten is so hard and durable this makes it brilliant for use on rigid cutting tools such as a magnetic based drill. As with everything Tungsten Carbide has a downside aswell. It is very brittle and will crack under thermal shock or physical impact. All in all a Tungsten Carbide Tipped annular cutter is a brilliant and durable tool.