Instructions:

Height: high (close)
Backness: back
Rounded: unrounded

Note: Used as Cardinal Vowel No. 16.

Occurrence:
Acehnese, Alekano, Azeri, Bashkir, Chinese (some Min Nan dialects, some Wu dialects, Xiang), Crimean Tatar, Garifuna, Irish (Ulster), Korean, Kyrgyz, Ongota, Sakha, Scottish Gaelic, Sundanese, Thai, Turkish, Turkmen, Vietnamese.
(Source: https://en.wikipedia.org/wiki/Close_back_unrounded_vowel#Occurrence)