600-Packs of 1/4? x 1/2? Aluminum Oxide Bands available in 60, 80, 120, 180, 240, 320 or 600 grit. This is NOT a typographical error! 600 packs, you choose which abrasive grit. A-4672-600 – 60 grit A-4673-600 – 80 grit A-4674-600 – 120 grit A-4675-600 – 180 grit A-4676-600 – 240 grit A-4677-600 – 320 grit A-4678-600 – 600 grit Use with mandrels A-SD328 or A-SD188. Made in USA. 40,000 RPM Max Speed. 3Ms Aluminum Oxide Abrasives are made of high-grade mineral and a bonding system that reduces shelling of the mineral. These economical abrasives are excellent for fast clean-up and pre-polishing work. Use the Sanding Bands with 3/32? (2.35mm) and 1/8? shank rubber drum mandrels. To install, slip band onto rubber drum with screw loose. When band is in position, tighten the screw, which expands the rubber drum, for a secure hold. *Optimum Operating Speeds are much lower (between 25% – 50% of maximum speeds) and also depend on the type of workpiece.