Lululemon fly and tie tank

Purchased used but looks new and I have never worn it. Cute eggplant heathered color with back detail and side sinching. There is no tag inside shirt but I am guessing it's a size 8?? Arm pit to arm pit measurement is 15 1/2 inches. Arm pit down to sinching area is 15 inches and the front and back lightly drapes. You can undue side sinches and shirt from shoulder to the bottom measures 28 1/4 inches.