The Sirena Rib Tank from Z Supply is made in their brand new Premium Feather Rib that has a heavier feel than you've felt before and is a go-to basic. It's made of 95% Cotton and 5% Spandex. Available in so many colors, it will be at the top of your Essentials list. Machine wash cold, gentle cycle, wash with like colors, do not bleach, tumble dry low, warm iron if needed.