[Advanced ]The rotary burrs are made of carbide, which is sharp and sturdy. And the hardness can reach to HRC70. The durability of carbide burr is 10 times higher than high speed steel cutter (HSS cutter). 200 times more than the small wheel durability. Comprehensive processing costs can be reduced by about 10 times. [Professsion 20 PCS Set]The carving bits include A, C, D, E, F, G, H, L, M and N type burrs. There are 2 sizes for each type burrs, which is 1/8 shank 1/8 head diameter and 1/8 shank 1/4 head diameter. They are suitable for almost everything you need for engraving, cutting, shaping, grinding, polishing and removing sharp edges. [Easy to Use] If the cutting bits are chipping easily this could be due to the speed being too slow. However, it's Perfect to start the cutting slow, increasing the speed as you go along. High speeds will prevent clogging in the of your burrs. The 1/8 carving burrs can bear the speed range of 6000-50000 revolutions per minute. [Widly Use]The 3mm and 6mm head diameter carbide cutting burrs set is widely used for metalwork, tool making, model engineering, wood carving, jewelry making,welding, chamfering, casting, deburring, grinding, cylinder head porting and sculpting. [Single Cut]Single cut burr provides large, wide evacuate the large chips easily and also prevent iron-chip accumulate and over-heat cause cutter head damage. It is more suitable for relatively high density materials such as iron, alloy steel, stainless steel etc. colour: silver Material: carbide Package Contents: 20 x Single Cut Rotary Burr Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.