For use with a 3M 6000 filter to provide combined particle and gas/vapour protection. A 3M 501 Filter Retainer is also required to attach the 3M 5911 P1 Filter to the mask. N.B. This 3M 5911 can also be used in isolation as a P1 particle filter however a filter retainer and a 3M 603 Platform must be used. Box of 30.