This lightweight and breathable impact-resistant shell easily inserts into any hat for protection against those every day 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 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. Not bulky like a hard hat, bump caps are typically worn in spaces where worker-generated impact head protection is needed, like low entry into a job shack, beams, low pipes and other bump hazards. *Does not replace a safety certified hard hat. One size fits all.