These masks keep nasty silica and asbestos out of your lungs with a whopping 99% filtration efficiency. The clever one-way valve means you won't be fogging up your glasses while working up a sweat. With a flexible nose bridge and adjustable straps, you'll get a snug fit that feels like a warm hug for your face. The anti-clogging inner layer ensures you stay cool and collected even during the toughest shifts.