Nylon, melt-blown with EAP filter technology Imported 6-layer full protection: BASE CAMP M Plus face mask is the third generation of BASE CAMP dust mask. Adopted EAPI filter technology and advanced nanotechnology, filters are upgraded to be 6 layers, which can maximally block exhaust gas, pollen, dust, particulates and smoke, etc. Provide reliable protection for daily use.More breathable & Comfortable: High quality mesh materials, the reusable face mask is 11.3% more breathable, strengthens airflow ability, dissipates heat, also reduces moisture inside to ensure smooth breathing with our breathable face mask. Meanwhile, its elasticity is 6.1% higher for more comfortable wearing.Adjustable for Best Fit: Designed with an adjustable hook-and-loop strap, the adjustable face mask can be adjusted to fit most people for the perfect fit. The closed AEB system helps hold the mesh mask without slipping off your head/face while relieving pressure or pain in your nose and ears. Tips: Please refer to picture 4 to take measurements before purchase.Prevent Goggle Fogging: Enlarged one-way valves are 26.3% more efficient at dissipating heat, water vapor, etc., decreasing humidity and preserving filter properties. It works with a flexible nose clip to seal face masks with filter around the nose to effectively prevent fogging. Get rid of the worries of glasses fogging up while working.Reusable & Washable: The activated carbon filter is replaceable after use, and the sports mask shell and valves can be detachable to be washed by hand when dirty.