Moldex 4700 AirWave N100 Respirator Mask, Medium/Large-Particulate Respirator Mask Moldex AirWave Industrial N100 with Valve Not Rated Adjustable Head Strap Medium / LargeExclusive easy breath wave design; less resistance and better breathability Contouring foam face seal applies less pressure for added comfort Soft cloth SmartStrap allows you to adjust for a customized fit SmartStrap allows the respirator to hang around the neck when not in use Dura Mesh shell resists collapsing in heat and humidity Molded nose bridge seals easily without a metal noseband FlexFit design moves easily with your face and stays in place