Postmark brand shirt from Anthropologie. It's their gingham chiffon overlay Elsie blouse.
preowned condition. some snags please see pics for condition.

nylon mesh overlay with horizontal stripes create a gingham effect when laid over vertical striped cotton lining.
bell sleeves
elastic cinched waist
pullover style

approx measurements when flat: armpit to armpit: 16", length: 21.5"