3M 2135 P3R Particulate Filters. Stand alone, lightweight particulate filters , Lightweight , Low breathing resistance , Bayonet fitting system ensures precise and safe locking , Versatility: can be used on all 3M 6000, 7000 and 7500 Series Half Masks and Full Face Masks , Maximum use concentration: 20xWEL (half mask) or 40xWEL (full face mask) , Standard: EN143  , Approval: CE marked , Workplace Exposure Limit