Aquascape BioBalls provide a textured surface area (19 sq. inches per BioBall) upon which beneficial bacteria can colonize and grow. The textured surface maximizes the available space for beneficial bacteria populations and water retention, and the paddle wheel design breaks water flow helping to de-gas and aerate water. The compact size of Aquascape BioBalls allows for placement into smaller areas. They are the ideal media for use in all biological filtration applications. Each box contains 100 BioBalls and a reusable mesh bag.