95% Polyester, 5% Spandex 
 
Sizing (Bust unstretched) To get this measurement we lay the top flat and measure from the side seam just under the sleeve to the other side seam, then double it to get the measurement of the circumference at the bust .  If unsure of fit, check one of your own favorite shirts of a similar style to compare.
Small - 32"
Medium - 35"
Large - 36"
XL - 38"