Cupio, black/charcoal striped sleeveless, cow neck dress, no size tag L or XL?

See tag pictures for material Like new NO SIZE TAG (looks like L or XL) streching material, but is loose fitting reminds of Old Navy dresses Like new, worn 1 or 2 times looks great with boots or heels Flares as it lengthens Neck line to hem 36" Arm pit to arm pit 18"