Nylon, Melt-blown with EAPI Filter Technology Imported 6-Layer Comprehensive Protection: BASE CAMP M Plus face mask is the third generation of BASE CAMP dust mask. Adopted EAPI filter technology and Advanced Nanotechnology, the filters are upgraded to be 6 layers, which can maximally block exhaust gas, pollen, dust, particles 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 the ability of air circulation, dissipates heat, also reduces moisture inside to ensure smooth breathing with our breathable face mask. Meanwhile, its elasticity is 6.1% higher for wearing more comfortable. Adjustable for Optimum Fit: Designed with adjustable hook and loop strap, the adjustable face mask can be adjusted to fit most people for snugly fit. Enclosed AEB system helps keep the mesh mask in place without slipping off from your head/face while relieve the pressure or pain in your nose and ears. Tips: Please refer to image 4 to take measurements before purchase. Avoid Glasses Fogging: Enlarged one-way valves are 26.3% more efficient in exhausting of heat, water vapor, etc, which decrease humidity and keep filters' property. It works with flexible nose clip to seal the face masks with filter around the nose to effectivly prevent fogging. Make you get rid of the concerns of glasses fogging while working. Reusable & Washable: The activated carbon filter is replaceable after time of usage, and the sports mask shell and valves can be detachable to wash by hand when get dirty.