CNZ BBS300 Bio-ball Filter Media for Aquarium Fish Pond Waterfall Fountain, 300-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 300 per bag These plastic bio-balls are a great media for use in all types of filters Weight: 840g Dimension: approximately 10" x 9" x 3.5" (flat)