This simple baseball cap is actually a deadly weapon. The
Sap Cap features a pocket on the back that has a "unique impact material that is 110% the density of lead and will not rust." This impact material is designed especially for whacking people on the head for protection. The instructions are to grab the bill of the cap and swing away. The Sap Cap retails for $30 USD.
I'm all for self-defense and feeling safe to walk in your hood, but to me this product screams "BAD IDEA!" I'm not sure who came up with the concept or who produces it, but I'll never sit comfortably at a sporting event again.