Saa3f90c1c4f74cb6b90ec7cddb4b7430I.jpg I Tested 4 1 2 Grinding Discs: Heres What You Need to Know! 50 PACK Grinding Wheels 4 1 2" x 1 4" x 7 8" Metal Steel Angle Grinder 3inch Grinding Wheels Cutting Disc Grinding Wheel Wear Resistant Angle. About this item : Grit Material Aluminum Oxide Item Dimensions LxWxH 9. 45 x 8. 86 x 4. 72 inches Compatible Devices Angle Grinder Grit Number 120 Color redDescription: Size: Diameter is 4 1 2, Arbor is 7 8, the flap disc is standard size and suitable for most air and electric grinders. Specification: Type #27, the grinder sanding discs are better for smoothing and blending surfaces. Maximum speed 13300 revolutions per minute (RPM), the wheels perform well. Package contains: 40 60 80 120 grit angle grinder sanding discs, 10 x 40 grit, 5 x 60 grit, 3 x 80 grit, 2 x 120 grit, the combination better matches your requirement.