Rubber Bonded Abrasive Discs A-D1-5 and A-D2-5 are suitable for grinding, smoothing and cleaning glass, high speed steel, and other tough materials. Recommended for use with Foredom Mandrels A-M1 and A-M6 (A-D1-5 Discs) and A-M6 and A-M15 (A-D2-5 Discs). 

Made in USA. 30,000 RPM Max Speed.

Both are 90 grit with 1/16″ arbor hole