The steel-pan is created by hammering a 55-gallon drum to produce the full chromatic range of scale notes. After the drum is hammered into the shape of a concave bowl, individual notes are grooved out into the bowl of the drum. The traditional steel-pan was hammered out by hand, but with the instrument gaining popularity and worldwide demand, manufacturers have experimented with more efficient methods including Spinforming, Flowforming, Aquaforming and Marforming. A typical pan contains 2½ octaves, with each note being a hammered out groove in the pan that produces a distinct note.