What is "hakgediya"

The hakgediya is a type of conch shell (the shell of a large marine gastropod mollusk) which is used as a kind of trumpet in the traditional ritualistic music and religious folk art-music of Sri Lanka, which has been somewhat influenced by Indian music. The hakgediya is an aerophone, or Susira (wind instrument or aerophone in the language of Pali). This instrument was used mainly in Theravada Buddhist artistic rituals which also involved other categories of instruments such as Ghana, Avanaddha, and Tat ( idiophones, membranophones and chordophones respectively).