High Function: Turn your Dremel or other rotary tool into versatile high-speed sander. Universal Size: 9pcs reusable sanding drum are divided into in 3 diameters: 1/2, 3/8 & 1/4". Common and standard size fits for all rotary tools like Dremel etc. Good Combination: It comes with 329 pieces sanding bands and 9 pieces sanding drum mandrels. Totally 338 pieces drum sanders set. These rotary sanding brands contain 3 sanding grits (60 grit, 120 grit, 320 grit) and 3 diameters (1/2”, 3/8” & 1/4").