Shop '47 Brand Women's Black Boston Celtics Serengeti Knit Beanie with Pom online at Macys.com. Soft and cozy, this Serengeti Knit beanie is the perfect way to keep warm on Boston Celtics game days. The black fabric of this '47 Brand cap pairs easily with most looks, while the furry pom on top adds a fun dose of personality. The contrasting Boston Celtics graphics are the perfect finishing touch to this comfy knit hat.