HQRP 2-Pack Wick Filter for Vornado EVAP1, EVAP2, EVAP3, Model 30 /Model 40 / Model 50 Humidifier + HQRP Coaster HQRP&reg; 2-pack Humidifier Wick Filter Replacement plus HQRP&reg; Coaster; Compatible with Vornado MD1-0002 / MD1-0001 Filter Replacement and All Vornado Evaporative Humidifiers; Absorbs hard water minerals and reduces scale build-up inside the humidifier; Replace at recommended intervals for best performance; 2 weeks DOA replacement warranty!