Winix standard replacement filter for the Winix PlasmaWave 9300 Ultimate Pet Air Purifier. One-year ultimate replacement filter set includes washable pre-filter, true HEPA filter, washable Advanced Odor Control Granular carbon filter and anti-microbial coating. Replace as indicated by filter change indicator (approx. every 12 months.) Pre-filter should be washed every 3 months; wash carbon filter as needed. Filter size 17. Model 17WC, Item# 114090. Fits Winix models P150, 9300 and 9000S.