Our material is two layers of 95% cotton and 5% spandex. They have adjustable ear straps so you can make them as tight to your face or as loose as needed for a more comfortable fit. All masks come with an aluminum nose pinch comfortably sewed into the mask material for a custom fit to your nose. Our medium masks are 4.7 inches and our large masks are 6 inches. To find your size, measure from the bridge of your nose to 1/2 inch under your chin. To ensure a succesful delivery, please remember to add your unit number in your shipping details.