Diameter 6″. Center hole thread size: 5/16-24 EXT. 3M Xtract proprietary multi-hole pattern provides superior dust extraction to prevent loading, increase productivity, and provide a cleaner work environment. One-piece threaded shank for low vibration and improved balance. Low profile firm density foam and blunt 35 degree tapered edge provide durability and an aggressive cut. 3M Hookit attachment system provides easy disc changes and optimizes disc life.