Coucou cotton Iris Tank in black. Measures 19" across at most stretched. Not a lot of give in this cotton and style. Coucou recommends sizing up if you have a larger chest. I normally wear L in Coucou and this is a bit tight. It's so cute though, I'm going to by an XL! Here is the product page https://coucouintimates.com/en-us/products/the-iris-tank-cotton-voile-black