SunSun PLUS Coarse Fine Filter Sponge Pad for SunSun HW402B Canister Filter (3 White + 1 Blue) by Sun Microsystems Convenient 3 packs fine filter pad replacements Includes 1pack coarse filter pad Fits Sunsun HW402B/505B and other re-branding canister filters Dimension: 7.0 " (L) x 7.0 " (W) x 0.75 " (H) Provides both mechanical and biological filtration