Ann Taylor loft dark tan sleeveless shirt size m

Ann Taylor loft dark tan sleeveless shirt size med. sides of shirt has ruffle along the sleeves. And elastic waist band. Under the right arm there is a small discolored spot. You can’t really see it as it’s covered by the ruffle. I only wore the shirt once to work so not sure how the stain got there. All items come from a pet and smoke free home