Bata drums are hourglass shaped, double headed, traditionally carved from a single log, and played as a set of three of differing size, iya, the largest, called the mother drum, itotele and okonkolo, each producing its own register within the ensemble.
Consecrated versus secular instruments
A set intended for religious use undergoes a specific consecration rite that seats the spirit Ana inside the drums, called fundamento, which makes a consecrated set categorically different from an otherwise identical looking set built for folkloric or educational performance, the wood and the hide are the same, the object's status is not.
Who may play and touch a fundamento set
Only initiated drummers, omo Ana, who have undergone the required rites may play or even touch a fundamento drum, and in most lineages women are traditionally excluded from playing or touching the consecrated set specifically, a real and frequently discussed restriction rather than an incidental custom. Non-consecrated batá used in secular or folkloric performance carry no such restriction and are played by trained musicians of any background, and re-heading a fundamento drum, unlike an ordinary one, involves its own ritual process rather than a simple repair.