Rotary burrs, HSS High speed steel burrs are used primarily for machining soft steel, aluminium, bronze, brass, etc High speed steel burrs are a better choice when optimal machining conditions cannot be maintained or, when the risk of vibration and impact shock are high Also usable with low cutting speeds Type of cut:M: Medium, for machining unhardened steel and other moderately hard materials under normal conditionsEC: Extra coarse, for soft materials when good stock removal is required. Counteracts chip build-up between teeth Packaging: Plastic box - Individually packed in boxes of 5