It is distinguished by a narrow panel (approx 1 inch wide) of the same blue with white narrow stripes down each side (beneath the armpit).
Size M, it is approximately 17.5 inches underarm to underarm, and 27.5 inches from nape of neck to hem.
Made of 100% very fine-knit cotton.
Lovely item, in very good condition - no stains, smells, snags, holes...!