Conch
Conch, white conch or dungkar (Skt. shankha; Wyl. dung dkar, Tib. dungkar) — a large white seashell which was used in Indian religious ceremonies, and also warfare, and was hence adopted in tantric Buddhist rituals. Usually one plays in a pair in which the musicians alternate in taking breath, to ensure the continuity of the sound.
Out of the four enlightened activities, the conch is related to pacifying.