Bring on the throwback heat, Red Sox fans! Throw on classic Boston style with the New Era Red Sox 9FIFTY A-Frame Classic Cap. As part of New Era’s 9FIFTY A-Frame Stacked Retro collection, this cap blends everyday comfort with a vintage-inspired design that sharpens your look. Give your Red Sox pride a timeless edge with the New Era Red Sox 9FIFTY A-Frame Classic Cap. Polyester fabric delivers lightweight durability. 100% polyester.