Kaval has 7 holes on the top and one from the bottom of the thumb of the left hand.
Generally, the lower part of kaval has a further 3 or 4 openings, which are always open.
They have the functions of resonant and are called "devil holes".
Legend tells about a shepherd who so beautifully played kaval that when the shepherd was asleep the devil tried to spoil him Flute
and took a few holes at the end of the instrument. They proved to be even more enrich the sound of instrument ;-).
Kaval is typically constructed from a hard wood.
In Bulgaria often uses wood dogwood (bul. Drian, dryan).
It can be met instruments made of different wood: grenadila, plum, pear, wood, pink, etc.
The material determines to some extent on the timbre of the instrument.
Storing and maintaining the instrument wooden instrument (oiling)
You should not dry out the instrument, therefore it is advisable to hold it in, eg. in foliwym bag.
After each playing an instrument should wipe the inside using a tube brush (eg. Cloth on a string).
From time to time (eg. Monthly) kaval must be lubricated with the oil (preferably olive or sunflower) and hold it in this condition a few days.
The new instrument is recommended lubricants oil and will hold a couple of weeks in plastic bags to instrument soaked with oil.
Oiling the instrument is intended to protect the wood from soaking water and before rupture.
Oiling the instrument makes the instrument darker, maintains itself, soaked with oil, and also causes a slight change of timbre of the instrument.