Mining safety kit s/m the sr 100 silicone half mask air purifying respirator is intended for use when maximum safety and breathing comfort are required. The heat-treated silicone material is fda approved offering a safe and comfortable fit that molds to the shape of your face. Extremely low breathing resistance makes this mask optimal for low to strenuous work activates. One mining safety kit includes everything you need. features a unique face seal design providing a high protection factor face piece is made of heat treated silicone with minimal risk of contact allergies double exhalation valve design providing only half the breathing resistance of competitive respirators high-efficiency p100 particulate filter with a minimum 99.997% filtration efficiency can be used with our p100 filter and/or a range of chemical cartridges which can be “piggy-backed” together extra large 201 square inch p100 filter area provides extremely low breathing resistance, high air flow and extended filter life delivered in a convenient storage box size small/medium easily adjustable v-shaped latex free elastic head harness with a large crown plate