PFERD'S Combi-Disc diamond abrasive mini grinding discs are available in four diameters (1", 1.5", 2", and 3"), and with fine, medium, and coarse grades. They feature both the CD and CDR types of popular locking mechanisms for easy on-off mounting. Ideal for work on jet engine materials, and on other exotic alloys like Hastelloy, Iconel, and titanium.