Size-adjustable; no replaceable parts Ideal for workplaces such as meat packing, food processing, pest control, meter reading, and automotive repair Perforated sides improves air circulation by allowing cross ventilation Interior plastic liner includes foam pad for additional comfort Standard version is molded from durable high-density polyethylene and is adjustable from size 6.5 to 8 NOTE: Bump caps do not meet the ANSI Z89.1-1997 standard, and are not designed to protect against impact of falling or glancing objects.