The khlui is a vertical duct

Fipple

A fipple is a constricted mouthpiece common to many end-blown woodwind instruments, such as the tin whistle and the recorder. These instruments are known variously as fipple flutes, duct flutes, or tubular-ducted flutes.-How it works:...

 flute

Flute

The flute is a musical instrument of the woodwind family. Unlike woodwind instruments with reeds, a flute is an aerophone or reedless wind instrument that produces its sound from the flow of air across an opening...

 from Thailand

Music of Thailand

The music of Thailand reflects its geographic position at the intersection of China and India, and reflects trade routes that have historically included Persia, Africa, Greece and Rome...

. It is generally made of bamboo

Bamboo

Bamboo is a group of perennial evergreens in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Giant bamboos are the largest members of the grass family....

, though instruments are also made from hardwood or plastic. The khlui is very similar to the Cambodian

Music of Cambodia

The music of Cambodia is derived both from traditions dating back to the ancient Khmer Empire and from the rapid Westernization of the popular music scene in modern times.-Folk and classical music:...

 khloy

Khloy

A khloy is an ancient traditional bamboo flute from Cambodia and more specifically the Khmer people. The khloy and other similar bamboo flutes can be found throughout Asia, due to bamboo’s abundance in the region. The khloy is a duct flute, about 15 inches long and 1 inch in diameter, with 8 or 9...

, though there are differences in tuning

Musical tuning

In music, there are two common meanings for tuning:* Tuning practice, the act of tuning an instrument or voice.* Tuning systems, the various systems of pitches used to tune an instrument, and their theoretical bases.-Tuning practice:...

 between the two instruments.

It comes in three sizes: khlui lib (ขลุ่ยหลิบ; small), khlui phiang aw (ขลุ่ยเพียงออ; medium), and khlui u (ขลุ่ยอู้; large).

The khlui once had a buzzing membrane similar to the Chinese di mo

Di mo

The dimo is a special membrane applied to the transverse Chinese flute called dizi , giving the instrument its characteristic buzzing timbre....

, but this is not used today.