BNWT Forme Core T-shirt (the brand Taylor Swift wears during her rehearsals) made to improve posture. It’s 2 layers so you can’t tell it’s a posture tee. In one picture you can see where I’ve pulled it inside out to the mesh side where you can see the gathering and the firm part under it. It’s black. I tried it on but I’m very long waisted so it doesn’t work for me. Their return policy isn’t good - which is a bummer since I paid $178.