The collet nut is made of brass, more durable than aluminum; the nut of pliers 4485 is made of brass, stable and wear-resistant; the special nickel treatment ensures that it does not rust easily. Fits more→Dremel 200, 285, 300, 3000, 395, 398, 400, 4000, 4300, 7700, 7750, 7760, 8000, 8100, 8200, 8220, Micro, Stylo+, Fortiflex and other rotary multi-tools. The special four-core collet fits perfectly with the nut, which keeps the nut firmly in the collet, easy to insert and replace. Multiple sizes: 1mm, 1.6mm, 2.3mm and 3.2mm can meet most needs and fit most accessories. NOTE: The collet set is not compatible with the Dremel 4200 Colour:gold Material:brass Package Contents: 1 set x for dremel