Argoul is a double reed oboe with a mouthpiece made out of two pieces of reed. One of the two reeds is used to produce a droning note and the other one is pierced with holes to obtain the melodic notes.
It is played with a system of continuous respiration that leads to a sustaining effect. The argoul is a very old instrument and it existed as early as the time of the Pharaohs. It's quite rare and only few people own or possess it.