Sleeves: Cotton / Polyester (Woven Fabric), Body: Cotton / Polyester (Knitting Fabric). Melting point is 230 degree Fahrenheit. Features: Turtle neck collar, All shirts are made of heat resistant fabric - No Melt, Lightweight and Breathable fabric- keep you dry, Storage Pockets with zip on Sleeves, Padded elbow patches, Loop Field on sleeve for all kind of patches/ flags. Please note: Chest measurement is made from 1 inch down from the armpits, Please kindly check the sizes and measurement at the photo section before your purchase, These are US Military sizes, It's bigger than retail sizes!!! Size S - Chest = 38 inches; Size M - Chest = 42 inches; Size L - Chest = 46 inches; Size XL - Chest = 50 inches; Size 2XL - Chest = 54 inches;