Compatible with 108oz/3.2L and 67oz/2L Stainless Steel Cat Water Fountain models (including PLWF003). Replace the carbon filter every 4 weeks; in hot weather, replace every 2 weeks to prevent bacterial growth. Replace the foam filter every two months to maintain fresh water. This set includes 8 carbon filters and 8 foam sponges for easy replacement and continuous pet protection. Three-layer filtration system: pre-filter traps hair and debris, middle activated carbon layer reduces chlorine, odors, and heavy metals, inner fine filter ensures cleaner, healthier flowing water. Always soak the filter in clean water for 5 minutes before use to ensure proper saturation. Do not install dry or soak directly in the fountain reservoir. Filter must be fully saturated prior to operation to prevent overflow. Materials: sponge. Color: white and black. Package contents: 8 x filter elements, 8 x filter sponges. Product does not include fountain or other accessories shown. Due to lighting and monitor differences, actual product color may vary slightly from images. Size variations of ±1–3 cm may occur due to manual measurement.