Alloy material, One-piece structure design, sturdy and durable, more than plastic models. The three-jaw chuck can hold these tiny bits more securely at high speeds, and the built-in spring is stable and durable. Quick change keyless chucks holds accessories with 1/32inch to 1/8inch sizes. Alloy steel material, wear-resistant, more durable and safe than other plastic materials. Use with brass collets, Strong adaptability, lmproved accuracy. Made of high-quality brass material, tough, more sturdy and durable, not easy to bend, 4 Claws design and workmanship strong holding power and hold the drill bit more firmly, more size of clamping diameter make them more versatile. Drill chuck collet set compatible with most tools you meet on the market. Easy and quick to change accessories without changing tools, including drill bits, buffing wheels, three-edged sharp knife, cut-off wheels, and more. You will get 28pcs drill chuck collet, including replacement keyless chuckX2, metal collet nutX4, brass 4485 colletsX20, super-thin open end wrench X1, L-wrench X 1. Colour: Material:alloy + brass Package Contents: 1set * for collet set Only the above package content, other products are not included. Note: Light reflection 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.