Selected filters in the range can be used in conjunction with a 3M™ 501 filter retainer and a 3M™ Gas & Vapour Filter to provide combined gas, vapour and particulate protection. Filters Class - PR3Product type - Particulate FilterCompatible Respirator - 3M™ Half Facepiece Respirators 6500QL SeriesConnection Type - BayonetFilter type - P3R.