No more grit in your sandwiches! Hi-tech mat filters out grains of sand on the beach. By DAILY MAIL REPORTER Updated: 03:43 EDT, 14 July 2011 ...

The N95 respirator mask filters at least 95% of particles that measure 0.3 microns. There's a lot of science to get to that 95-percent-or-better number that home sewers simply can't replicate.