Modern Vintage Mochanso Vibrant Tropical Print One-Button Lightweight Blazer

Modern Vintage Mochanso Vibrant Tropical Print One-Button Lightweight Blazer its tag as size smal, but runs small, probably an xs or xxs. the sleeves are fitted. for reference, i have chunkier upper arms, i can wear an XS even an XXS for as long as sleeves are not fitted or its sleeveless. This top fits me, but the upper sleeves are tight. front is lined, back is not. no fabric content tag, but fabric looks like a poplin. faux welt pockets with flap (pockets not functional approximate measurements taken laid flat across shoulder: pit to pit: 16" waist: 14.5" length: 27" sleeve: 17"