Fabletics | Workout Tank

Fabletics workout tank. Red and black. Pretty mesh detailing on the shoulder straps, and cute back cut out. There is no size tag. Thinking it is a bigger small or a smaller medium, and because of bust size and Fabletics size guide, I am labeling under size small. Please advise the measurements. Bust = about 15 inches. Length from top of shoulder to bottom of front just shy of 25 inches. Pre-owned, does show signs of wear (pilling). Please advise pictures :)