<unk>  (also known as "ringed hair") is a genetic trait in which the hair seems ‘banded‘ by alternating segments of light and dark color when seen in reflected light.
Pili annulati
Pili pseudoannulati
Pili multigemini
Lipoatrophia annularis
Balanitis circinata
Soemmering ring
Keratosis pilaris atrophicans faciei
Keratosis pilaris atrophicans