As the stone wears, its diameter reduces and so in effect the speed of the wheel’s rotation is increased. On most machines you cannot do anything about this, but with the WG200 you can lower the speed to compensate. In addition, when you want to remove material more quickly you can increase the speed of the stone. For added safety, its left hand nut thread ensures the grinding wheel is held securely with no danger of unwinding. Supplied with: 1 x WG250/K Diamond Truing Tool, 1 x WG250/C Straight Edge Jig, 1 x WG250/P Support Arm, 1 x WG250/R Stone Grader, 1 x WG250/S Metal Polish, 1 x WG250/T Angle Setting Gauge & 1 x WG250/U Angle Finder. Input Power: 160 Watt. Disc Speed: 150-250rpm. Stone Size: 200 x 40mm. Honing Wheel Size: 185 x 30mm.