Penn-Plax Undergravel Aquarium Filter for 10 Gallon Tanks – Two 9.5” x 9.5” Plates – Under Gravel System for Clear, Clean Water – Safe for Freshwater and Saltwater TanksBrand: Penn Plax Color: Blue Features: NOTHING LIKE OLD SCHOOL: The Clear Free Premium Under Gravel Filter is air driven and utilizes an Air Pump (not included) to cycle crystal clear water throughout your aquarium, while keeping a crisp and neat look inside. This means theres less moving parts, making for simplistic and easy maintenance. This filter is suitable for most 10 gallon aquariums. BIOLOGICAL, CHEMICAL, AND PHYSICAL FILTRATION: As air is