Professional Kit: There are 20 different shapes and sizes of rotary cutters, you can choose different types of cutter heads according to work needs, they will satisfy your different craft creation needs. Mutifunctional Tool: Diamond drill bits have 20 different grinding bits for carving, engraving, chamfering, grooving, reaming, punching, etc. and it is a good tool for detailed work. Quality Material: The countersink bits is made of quality high speed steel with long life, has the advantages of high hardness, good wear resistance and heat resistance. Compatibility: 1/8" (3.1mm) shank, 39mm length, fit for dremel electric rotary tool and most mini grinder. User-friendly design and easy insertion process, incredibly easy to use. Wide Usage: The wood dremel cutter can work on soft metals such as plastic, ceiling, drywall, laminate, fiberglass, vinyl, aluminum, etc. it is an ideal for DIYers, jewelers, designers, etc. < Hardware: HSS (High Speed Steel) Shank Diameter: 1/8" (3.1mm) Total Length: 3/4" (40mm) Box Contents: 20 X Rotary Burrs 1.When using drill bits, material temperature will be very high, please add water or coolant to avoid being burned. 2.For better tool protection, perfect for wood, plastic and materials has not so high hardness, it is better not to apply to stone or other hard material which may shorten the period of use. < < < < Quantity delivered: 20 pieces