Please Note: THE STYLE OF THE BLACK VEST IS A LOOSE FIT. You need to take one size SMALLER than your normal size if you want a slim fit (such as MS). Please purchase your waist grith before purchase, if you receive our sweat suit and are not satisfied with them, we guarantee a full refund or exchange.Premium & Comfy Materials: The sweat suit is composed of 15% Polyester + 70% Neoprene + 15% Nylon. The moisture-absorbing material allows it to absorb sweat while you're sweating, keeping your skin dry and providing better comfort. We recommend that you leave it in the air for 1-2 days after receipt to remove the smell of Neoprene material.Hand Wash OnlyFastening: ZipLooseEasy to Wear: Normal sweat vests may be inconvenient to take off after you've worked out, but our gym tank top takes a zipper design, high stretch and quick drying fabric makes it easier to put on and take off, making exercising easier