MESH CONSTRUCTION - The pollution mask is made of Nylon which offers excellent permeability. The lightweight air face mask is comfortable, breathable and good to wear in hot weather. PERFECT DESIGN - Anti pollution mask with adjustable nose clip, hanging Ear Design and removable hook & loop Strap, it helps effective seal and prevents fogging, keeps the mask from slipping. The image 3 show how to take accurate measurements of your face size to get your face size and make the right purchase. NEARLY ZERO AIR OBSTRUCTION - Dual one-way discharge valves and mesh material design of the air mask make air resistance smaller without sacrificing filtration. MULTIFUNCTIONAL - The dust face mask filters out 99-percent of exhaust, dust, particles, pollen, smoke and fumes. The M dust mask is suitable for people with woodworking painting mowing running cycling hiking and other outdoor activities.