SUN SunSun PLUS Coarse Fine Filter Sponge Pad for SunSun HW303 Canister Filter Microsystems Convenient 3 packs fine filter pad replacements Includes 1pack coarse filter pad Fits Sunsun HW303 and other re-branding canister filters Dimension: 7.5 " (L) x 7.5 " (W) x 0.75 " (H) Provides both mechanical and biological filtration