Trend FAST TRACK Replacement Stones are made from monocrystalline diamond with a unique diamond cross relief pattern for optimal abrasion rates. This helps to maximise sharpening efficiency and reduce clogging. Diamonds are held by nickel plating to a steel substrate, with ABS plastic base. This Trend FTS/S/R FAST TRACK Replacement Stone has the following specification Grade Extra Extra Coarse Grit 100 (nom. 60 micron) Dimensions 75 x 24 x 4mm Colour Grey