Nabal

The nabal is classified as the only brass instrument among the Korean instruments, It is also pronunciated as nap'al, but it is also substituted custemary by the name, nabal. The nabal can generate only one note by sustaining or stopping the note like a nagak. It must have been a very popular instrument for processional music, especially in Tae-ch'wit'a from a saying - "a high-ranking officer will immediately arrive as the nabal has already blown". The nabal is also used in Nong'ak of P'ungmullori and it has function for ignaling the start of performance as well as the departure of processional.
When not being used, the nabal does have a device for keeping conveniently, marking it shorter by pushing up the parts which are
separated when belong used.