The Skullerz 8945 Universal Bump Cap Insert is a lightweight, impact-resistant shell that easily inserts into any baseball cap, hat or other headwear for protection against bumps, scrapes, bruises and other minor head injuries. With flexible sides and convenient trim-to-fit customization, this bump cap insert easily fits a variety of hats/caps and head shapes. The shell is made of lightweight, durable polypropylene and designed with maximum ventilation for breathable airflow that