This is an excellent dust mask. Not only does it have a lower profile and weigh much less than conventional respirators, it also has an outstanding efficiency rating (NIOSH P100, capturing 99.97% of airborne particles 0.3 microns and larger). For those who remember the old Dustfoe mask, it is a long-awaited substitute. The mask is made of a flexible, hypoallergenic polymer that conforms to the face for comfort and forms a dependable seal. It has two adjustable elastic headbands for a secure fit and an exhalation valve that permits easy breathing and helps prevent your glasses from fogging. A sturdy grill keeps the filter off wet or dirty surfaces if you set the mask down. Supplied with a pair of long-lasting filters, rated for one month of continuous industrial use; replacements available separately. The respirator comes in two sizes (large fits about 70% of users). Made in U.K.