Let us exceed your expectations with the extended life of this BlueFire ZA ZA Type 27  Norton grinding wheel. Its advanced zirconia-alumina/premium aluminum oxide grit produces a tough face that can last up to two or three times the working life of pure aluminum oxide wheels. This Norton grinding wheel has a 0.25-inch central depression gives it just the right shape for a convenient 30-degree angle grind for light-to-heavy duty jobs. Useful across a range of applications, this versatile Norton grinding wheel for your right angle grinder is ideal for working with hard and soft steel alloys, including the 400-series and hard carbon steel mixes. Norton - Grinding Wheel - 66252843213 - Black Aluminum Zirconia - 24 Grit 4-1/2"x5/8"