- With a single layer of MagiCotton, your Gynecomastia Tank works wonderfully in flattening your chest. From the Core fibers of 35% spandex and 24% nylon wrapped with 41% pure cotton, this fabric stretches four ways, providing you with the best fit and compression in total comfort. The compression is focused only in the chest area. The mid-section is relaxed and filled with 100% combed cotton so you only feel the compression where you need it. An amazing level of compression with the feel of cotton and in a single layer of fabric. Made in the USA by Manshape?.