Take your streetwear game up a notch with the New Era Red Sox 9FORTY A-Frame UPSD Arch Cap. Crafted from 100% polyester, this baseball cap resists shrinking and stretching for a consistent fit and all-day comfort. Step into the next matchup and cheer on your squad in style with the New Era Red Sox 9FORTY A-Frame UPSD Arch Cap. Part of the 9FORTY A-Frame Arched collection. 100% polyester.