Open back dress, marbled knit fabric, ruched bottom, marked L but fits S

Dress with blouson top and exposed back. The lower band has ruched sides. Can be worn as a blouson shirt by pulling lower band up around the hips. Polyester knit fabric with marbled print. Marked L, but fits much smaller. (I’m size 4.) Mannequin’s measurements are 34/26/36, with a B cup. Pit to pit flat measure 19” Bottom band flat measure unstretched 15 1/2”, stretches to 20” Very good gently used condition. From a smoke free and pet free home.