CNZ BBS500 Bio-ball Filter Media for Aquarium Fish Pond Waterfall Fountain, 500-count Includes a free mesh bag Will not compact like other soft media, reduces channeling of water around media 1 Inch in diameter, black in color, approximately 500 per bag These plastic bio-balls are a great media for use in all types of filters Weight: 1300g Dimension: approximately 14" x 10" x 3.5" (flat)