Thai boxers are graded from fly weight to heavy weight, but welter, middle and heavy weight fights are rare.
At the opening sound of music, the two boxers in the ring will perform a short ritual of 'Wai Khru' (paying homage to the teachers) and this quite often proceeds to a staging of the Four-faced Brahman dance which symbolizes four virtues: compassion, temperance, prudence and justice.
They fight 3 minutes rounds alternated by 2 minutes rest periods.