P3 filter for use with STS half and full face masks. Certified and fully compliant with Australian/New Zealand Standard regarding respiratory protective devices AS/NZS 1716:2012. Filter 99.95% of particulates. Mechanical filtration doesn't lose filtration efficiency as it gets full or wet. Filters are water and oil repellent. Hard casing protects filter material from damage. Two required per mask. For use with RS01, RS01S, RX01, CF01, FS01 Dimensions: 77mm (dia) x 21mm (H), Weight: 22g