10pcs 40mm Diamond Grinding Wheel Cutting Disc with 2 Mandrels for Dremel Rotary Tool Ideal for cutting all kinds of metal, gem, stone, tile, glass, jade, ect.Material: Diamond; Wheel Diameter: 40mm; Rod Shank Diameter: 3mm; Max Speed: 20,000 RPM; Grit: 80Made of powder alloy, hot forming, high hardness, abrasion resistance, good impact. It's dry wet amphibious, small slot and high shapeness.Dremel diamond cutting wheel (disc) 40mm