This 20 pcs electric polishing kits are for DIY polished engraving, cutting, polishing (wood, plastic polishing purposes). These are all high quality high speed steel tools with 3mm shank.

Specifications:
Material: High Speed Steel
Shank Diameter: 3mm / 0.118in
Total Length: 40mm / 1.57in 
Package Size: 7.5 * 6.5 * 0.5cm / 2.95 * 2.56 * 0.19in
Package Weight: 57g / 2.01oz

Note:
For better function and tool protection, this set is not suitable for engraving hard wood, metal or stone.
It is suitable for wood, plastic and materials doesn't have so high hardness.

Package List:
20 * High Speed Steel Rotary Burs