Heavy duty 36 grit aluminium oxide. For general grinding and tool sharpening. Suitable for use on ferrous metals and alloys. 25.4mm (1″) bore with 12.7mm (1/2″), 15.88mm (5/8″) and 19.05mm (3/4″) reducing bushes. For use with all 150mm bench grinders. Heavy duty 36 grit aluminium oxide. For general grinding and tool sharpening. Suitable for use on ferrous metals and alloys. 25.4mm (1″) bore with 12.7mm (1/2″), 15.88mm (5/8″) and 19.05mm (3/4″) reducing bushes. For use with all 150mm bench grinders.