It consists of a set of 4 toothed wheels 7.5cm dia, mounted on a spindle and spaced 6mm apart. The ratio of teeth is 4:5:6:8. It is used with Whirling Table.
It consists of a disc having four rows of holes arranged in a circle, all equally distant from one-another and a blow pipe to blow air on the holes to get a clear musical note. It is fitted with a spindle to attach it with the whirling table.