Protex Respirator S3 Mask, Pack of 20S3 Single use filtering mask for use against solid and non volatile liquid particles At least 90% effective against fine dust and can be used for protection where the level of contamination is up to 10 times the Occupational Exposure Limit Comfortable during an 8 hour shift Advanced filtration system for medium performance 100% soft cool cotton linings which mould easily to shape the face Easy to breathe and talk through Not washable