Narrow band (4)
(Other definitions for belt that I've seen before include "Broad stripe" , "Waist band; hit very hard" , "See 18" , "sock or > tie" , "Cincture" .)
(Other definitions for stripe that I've seen before include "Band of colour, maybe of rank" , "Military rank indicator" , "Length of material, maybe showing rank" , "Priest (anag)" , "Long band of a different colour" .)