Face mask carbon filter suitable for 72 hours of use before its recommended to be replaced. It will filter particles as small as 2.5 microns in size. Each filter is stamped with the mark PM2.5 which stands for Particulate Matter 2.5 microns. Suitable for LL8894 Deluxe Face Masks or masks that have an internal pocket to insert an extra layer of protection. Colours Available: White. Materials: Carbon. Item Size: 115 x 80mm (LxH).