2 Pack, Paint & Pesticide Replacement Cartridge, Lightweight Cartridges/Prefilters Are Easy To Block For Fit Checks, Approved To R95/OV Category, R95 Filters Are At Least 95% Efficient Against Oil Based Contaminants & Resist Degradation For At Least An 8 Hour Shift, OV Classification Means That The Cartridge Is Approved For Organic Vapors, Used In MSA #10059410, True Value #541-175.