Akohẹn, or ivory horns, are played by members of the Ikpakoen (guild of ivory hornblowers), while Oko, or flutes, are played by members of the Ikpeziken (guild of royal flute players). Among the Emwin Arhe (royal treasures), Oko and Akohẹn are usually depicted being played by brass-cast figures representing members of these guilds, and also appear on Ama-Ẹrọnmwọn (bronze relief plaques), Aken'ni Elao (carved altar tusks), and Urhotọ (altar tableau).

Today in Benin City, when a public procession leaves the palace, a court official may sound side-blown horns made from ivory. Historically, these instruments were also used during warfare, where they were played alongside Ema (drums) and Ẹroro (bells), producing a “cacophony of sound” whose “[t]he psychological effect of the barrage of noise magnified the size of Benin’s forces” ( ).

Some Oko/Akohẹn were also cast in brass by members of the Igun-Ẹrọnmwọn. However, these brass examples are understood not to have been functional instruments and could not have been blown like their ivory counterparts ( ).