Sunsun HW-304B White Blue Pad HW-304 Canister White and Coarse Filter Pad 4 White Pads and 1 Blue Coarse Pad Fits SunSun HW-304B and other re-branded canister filters Dimension: 8.5 (L) x 8.5 (W) x 0.75 (H) Provides both mechanical and biological filtration