It was a natural trumpet that was created from a sea shell in which a hole had been opened (by breaking off the three first coils) for the blowing of air. The most suitable shells for this purpose were the “triton” (trumpet shell), the “cassis” (helmet shell) and the “strombus” (true conch).
The sound was produced with direct blow in the hole and the suitable lip technique. In the Minoan cult, they used side-blown shells of the triton type.