Product Description Item Number | 818342MSA's Flexi-Filter pads are low profile and flexible to fit under a welding hood and other personal protective equipment. They offer great balance and weight distribution for maintaining a good face seal, while their swept-back design provides vision and comfort. P100-Particulate Filter (99.97% Filter efficiency level) effective against all particulate aerosols 0.3 micron DOP.Flexi-Filters fit all Advantage Series respirators. Reviews 5 Filter PS 100 pads Posted by John Deible on Jan 13th 2017 Filters arrived in good time. The filters are as advertised. I will definitely buy from this company again.