describe Package content: 30 round wheels (225 mm, 6 holes, grit 120). High quality: the grinding wheel is equipped with a thick D-grade paper base, made of high-quality alumina and wear-resistant sand, and the high-strength resin bonding system increases the service life of life. EASY TO CHANGE: Durable reverse sticker makes changing wheels easier and more convenient; the shackle allows for faster assembly. Sizes available: 225mm/9" diameter with 6 pre-drilled holes for dust collection, suitable for random orbital sanders/sanding/polishing/rusting. Multi-functional grinding wheel: suitable for grinding and polishing wood, jewelry, glass, stone, automotive, machinery, metal, non-metal, rubber, leather, plastic, etc. Size: 9 inches Package includes: 30 round grinding wheels