Tassa is a form of kettle drum, presumably of Persian derivation that was brought to the Caribbean by indentured Indian workers durin gthe 19th centruy. It is made by tightly covering a clay shell with goat skin; early versions were covered in monkey skin as well. When ready to play, the goat skin is heated by aid of a fire to tighten the head, making the pitch higher. Modern versions are made of metal 'fiberglass' clay pots with a plastic head that is tightened with screws or even a plastic head that is tied on to the pot. These last longer and do not have to be adjusted as frequently.