Half Mask Face Piece Professional Silicone, Large with 2 Pair G71 OV/P100 Cartridges The Gerson Half-Mask with our G71 combination OV/P100 Cartridges is the recommended solution:. NIOSH-Approved protection for metal fumes that are generated during Aluminum Welding.. NIOSH-Approved particulate filter provides at least 99.97% filtration efficiency against particulates generated in sanding and grinding applications in the Body Shop*.. Relief from the irritating effects of nuisance level Ozone**.. NIOSH-Approved protection for Paint-Spray and other Organic Vapors.* 9361