Aluminum Oxide Separating Discs generally run cooler than Silicon Carbide Discs. For cutting cobalt and other non-precious metals. Have ¹⁄₁₆" arbor holes and are used with miniature mandrels (see related products below). Will cut on the edge and both sides. Measure ¹⁵⁄₁₆” in diameter by 0.025” thick ( 24 mm x 0.64 mm approx.) Maximum speed: 21,000 RPM. In boxes of 100 pieces. Made in USA.