Universal Safety Cap Insert Hat Liner Insert Hard Hat Insert Head Protection Style E.Safety cap insert provides great head protection and effectively protects against bumps, scrapes, bruises, etc.The hat insert are made of high quality ABS and sponge material, which is sturdy, wear resistant, durable, and does not break or crack.Insert is designed to not be stiff or bulky, and venting holes enhance breathability to keep cool.Cap Circumference 54cm-59cm/21.26inch-23.23inch, to fit different cap designs or baseball hats.Baseball caps insert is perfectly suitable for automobile assembly, maintenance, working, machining, industrial manufacturing, etc.Safety Cap Insert Universal Hats Lightweight. Baseball Hat Insert Breathable Head Protection. Hard Hat Shell Insert for Baseball Cap Protective. Baseball Hat Accessories Safety Baseball Cap. Outdoor Sports Personal Protective Equipment.