Ideal for use in ponds up to 500 gallons and is compatible with most pond pumps. The pond boss® Universal Pump Filter Box cleans water and protects pump from debris with the use of prefiltration. BioBalls promotes the colonization of beneficial bacteria for a biological filtration. Ideal for use in ponds up to 500 gallons. Works with most pond pumps. Cleans water. Protects pump from debris. Promotes growth of beneficial bacteria. Includes: Filter box, coarse filter pad, fine filter pad, and BioBalls. Dimensions: 12.25 in. x 6.25 in. x 6 in.