The Next Generation Of Our Best-Selling Skullerz 8945 Insert, The 8945F(X) Universal Bump Cap Insert With Extra Venting Delivers Enhanced Breathability And Up To 35% More Crown Impact Protection. This Lightweight And Breathable Impact-Resistant Shell 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 Polyethylene With A Ribbed Top For Stronger Crown Impact Protection. All-Over Venting Maximizes Airflow For Cool Comfort, While An Interior Foam Pad Reduces Impact Without Absorbing Odors For Fresh All-Day Wear.