POND FILTER PAD 2" Thick 28" x 24" Koi Goldfish Media by Aqua-Flo
You'll see it featured in every major Pond & Koi & Fish Care Magazine. Beige (COARSE DENSITY) Aqua-Flo Mat Filter Pad 28" x 24" x 2". Excellent surface area per sq. ft. with good adhesion of nitrifying bacteria.