Package Includes - Comes with 504 sanding bands, 24 sanding drum mandrels, 2 self-tightening drill chucks and 1 combination wrench, 531 pieces in total in 1 set 7 Grit Essential Accessory - These sanding brands contain 6 sanding grits (80 grit, 120 grit, 150 grit, 240 grit, 320 grit, 400 grit, 600 grit) and 3 diameters (1/2", 3/8" and 1/4"). Each grit and size has 24 sanding bands for use and replacement Universal Drum Mandrels - The 24 pieces reusable drum mandrels contain 3 diameters: 1/2", 3/8" and 1/4", 8 pieces for each size. Common and standard size suitable for all rotary tools like Dremel, etc. Easy to install - make sure the drum has been screwed on tightly, drum mandrels with self-expanding rubber cushion, which makes the sanding bands close to the mandrel firmly and achieves a better finish; Note: Please wear professional safety glasses to protect your eyes because there may be flying grains when the sanding drum rotates at high speed Wide Compatibility - Standard and