Compatible Models: Replacement filter compatible with Philips AMF220/15 HU3918 HU3916 HU3915 HU2718 HU2716, FY3446/30 replacement parts. Set Value: Replacement filter kit contains 2 humidifier replacement parts. HEPA Filter Layer: This HEPA filter can capture up to 99.97% of fine particles with a size of only 0.3 microns. Stable Output: This filter can filter hard water, so that the humidification function continues to stabilize. Replacement Reminder: To ensure the effectiveness of the air purifier, it is recommended to replace the filters every 3-4 months.