Material: Our products are all metals, the claws and springs of the chuck are heat-treated at high temperatures, very durable and have good concentricity. Easy to change: You can quickly and easily change to rotary drill accessories without key or adapter. It saves your time and also makes you no need to buy other accessories. Claws: The clamping range of the claws is 0.4-3.2mm. There is a large range for many sizes of drill bits. Please noice your drill sizes before you. Suitable: The keyless chuck is suitable for 4000, 400,3000, 398, 395, 300, 285, 275, 200, 100, 8200, 800, 780, 770 , 7700, 750 models of Dremel rotary tools. It's not suitable for 8050-N/18 because the axle of the machine is too short. Wide usage: The drill chuck is used in electric grinding machine, nailing machine, engraving machine. It is very useful for auto repair shops, garages, warehouses, workshops, factories, offices and even at home.