Features Good Compatibility: This straight shank chuck has good compatibility with most rotary tools used in hardware, hobbies, home and more. Excellent High Carbon Steel: This straight shank collet is made of excellent high carbon steel, which has good elasticity, wear resistance, is not easily damaged and has a long service life. Multiple Size: This straight shank chuck is available in four sizes: 4 mm, 5 mm, 6 mm and 8 mm to meet most of your needs, so you can choose the chuck you need according to your requirements. 4 Jaw Construction: This straight shank chuck has a 4 jaw construction to provide good contact and a more powerful grip. Wide Application: This straight shank chuck is suitable for grinding and polishing metal parts such as cylinder heads, valve ports and small industrial parts, and for holding grinding heads in various grinding machines, suitable for repairing and grindin Specification: Item Type: Straight Shank Collet Set Material: High Carbon Steel Collet Size: Approx. 4mm/0.16in, Approx. 5mm/0.2in, Approx. 6mm/0.24in, Approx. 8mm/0.31in Package List: 4 x Collet 4 x Storage Box Package List 4 x Collet 4 x Storage Box