Boston Red Sox '47 Alpine 1/2 Zip Sweatshirt - Grey. The '47 Alpine Fleece Pullover is made from soft and warm 100% polyester polar fleece with an upper woven overlay. The matte-coated zipper and woven patch have vibrant graphics. 100% Polyester Polar Fleece, - Matte-Coated Zipper, Woven Patch