D.Zefron Compression Men's Shirts Base Layer Short Sleeveless Shirts BE AWARE!! : We revised SIZE GUIDE PHOTO already, Don't need to go up a size, check the D.Zefron Size Guide Photo! 3/N coverstitch top and bottom, 1/4" gauge Feed-off-the-arm Sewing Technologies UV Protective Skin Care Fabric, machine washable, tough construction, built to last Material : 90% Polyester / 10% Spandex / Garment Care : Machine Washable Quick Dry, 4Way Stretch, Light wight, Air Permeability