Face mask (filtering facepiece respirator) FFP3 with exhalation valve Filtering half mask, reusable elastomeric respirator with pink replaceable pancake filters Full-face elastomeric respirators seal better.Mechanical filters are a class of filter for air-purifying respirators that<unk> ly stops particulates from reaching the wearer's nose and mouth. They come in multiple physical forms.
Mechanical filter 
Flow diverter
Articulatory technique
Vascular closure device
Pulmonary thrombectomy
Syringe filter
Thrombectomy
Pericardiectomy