The Gang-Su ritual is announced by the playing of musical instruments from the balcony of the gompa. The two young monks facing each other play a solo on the dung-khar instrument to invite the other monks for the ceremony. The Tantric Gang-Su ritual is conducted to protect the gods and goddesses, the monks, the monastery,and the dharma from any calamities. Gang-Su is also a tantric deity (divine mother) depicted in the gompa in a sexual union with Buddha. 'Dung-khar' is a shankh trumpet which may or may not have a mouth piece. This aerophonic instrument symbolises the 'om' sound. It is played in pairs and is used to call the monks to the pujas and also in the monastic orchestra.