The 3M 4251 Valved Reusable Half Face Mask is a maintenance-free half face mask designed for effective and wearable protection against a combination of gases, vapours and particulate hazards. This 3M 4257 Respirator Face Mask is APF10 for particulates and offers essential respiratory protection by using unique integral filter technology to keep you safe in any industry. The 3M 4251 is ideal for use with: general paint spraying, adhesive spraying, creosoting, solvent spraying, paint stripping, boat building, vehicle manufacturing.