RZ Dust/Pollution Mask Bonus Pack w/5 Laboratory Tested Filters Model M2, Mesh, Grey, Size Large RZ Industries Exclusive online Bonus Pack with 5 Active Carbon filters - Sizing: Medium - (75lbs - 125lbs) Large - (125lbs- 215lbs) Extra Large - (215lbs+) Laboratory tested at Nelson Laboratories, Salt Lake City, UT 99.9% to .1 Micron RZ Mask is a Patent Pending Air filtration mask, 100% Customer guarantee *** Dual-Exhalation Valve System removes moisture / Anti Fog Adjustable Nose System Includes 5 Replaceable 99.9% Active Carbon Filters / RZ Online Special