Features: Durable Material Collet chuck set is made of high quality carbon steel which is strong, durable and can use for a long time. Stable Performance Collet chuck set has a stable performance due to its unique precision and quality. Practical It can help you make better, more efficient and more durable processing products. The chuck Can be converted into 6mm handles, 6.35mm handles and 8mm handles. Material: carbon steel Size: 6/6.35/8mm Package includes: Collet Chuck Adapter, Nut