As per IS: 2386 ( Part IV). For determination of resistance of aggregates to wear by abrasion. It comprises of two hollow cylinders, closed at one end and provided with tight fitting covers at the other end, are mounted on a shaft at an angle of 30 degrees with the axis of rotation. The shaft rotates at 30-33 RPM through a reduction gear, coupled to a motor suitable for operation on 440 volts, 3 phase, A.C. supply. The unit is supplied complete with a revolution counter and abrasive charges.