Amazon.com - WuYan 2pcs Black Replacement Filters for Philips HU4102 Humidifier Wick Replacement Filters,Compatible with HU4801 HU4802 HU4803 Humidifier Parts
HQRP Wick Filter Compatible with Philips HU4801, HU4801/01, HU4802, HU4802/ 01, HU4803, HU4803/01 Humidifier, HU4102 White - Walmart.com
LifeSupplyUSA Replacement Wick Air Filter fits Philips HU4101 HU4801 HU4901 2000 Series Humidifiers ER712 - The Home Depot