The N-Ferno 6811Z Zippered Rib Knit Beanie Hat is a soft cuffed beanie with an opening to add in our Skullerz 8945 Universal Bump Cap Insert (sold separately) for added head protection for those cold winter jobs. This winter hat is made with 100% soft dry acrylic with 40-gram 3M flex stretch insulation for warmth and a comfortable fit. A zippered compartment placed on the back of the hat opens to insert a bump cap, turning it into a protective, yet warm beanie. Bump caps are typically worn in spaces where worker-generated impact head protection is needed, like low ceilings, beams, low pipes and other bump hazards. It helps protect against bumps, scrapes, bruises and other minor head injuries. The Skullerz 8945 Universal Bump Cap Insert (sold separately) is a lightweight, impact-resistant shell that features a foam pad inside for additional impact protection and comfort against the head. Worn alone, this ribbed knit beanie hat is soft and warm for cold weather work. Great for construction, airline workers, baggage handlers, aircraft manufacturing & maintenance, warehousing/distribution, heavy equipment & machinery assembly, mechanics, confined space work, HVAC & electrical work, and installation.