• Philips NanoProtect HEPA filter FY3400/30 3400 series, lifetime up to 1 year, 3-layer HEPA filter system, original filter for PureProtect 3400 air purifier compatible with 3400 series air purifiers and humidifiers (AC342x) Effectively captures 99.97% of the nanoparticles (1) Life up to 1 year compatible with 3400 series Box contents: 1 filter Original Philips filter PureProtect Water, replacement filter for Philips PureProtect 3400 series 2-in-1 air purifier and humidifier compatible with 3400 series: AC3420, AC3421. The air purifier model is indicated at the bottom of the device. Durable filter Filters with a service life of up to 1 year provide optimum filtration performance of up to 1 year (2), thus reducing labor and cost. Vacuum the pre-filter periodically to improve filtration. Original Philips filter for best performance. The original Philips filter is designed to fit your device perfectly. Always use the original Philips filter for best performance. 3-step HEPA filtering captures 99.97%of the smallest particles. The pre-filter, NanoProtect HEPA filter, and 3-step filtration of activated carbon capture 99.97% of particles up to 0.003 microns to protect you from contaminants, viruses, allergens, bacteria, and odors (1). Follow the smart filter status indicator on your device. Your Philips device will