RZ Dust/Pollution Mask Bonus Pack w/5 Laboratory Tested Filters, Model M1, Natural, Size XL RZ Industries Exclusive on line Bonus Pack with 5 Active Carbon filters 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