Penn Plax Deluxe Bubble Disk Aerating Aquarium Stone (Large) and 20ft of Silicone Airline Tubing Penn Plax Deluxe Bubble Disk Aerating Aquarium Stone (Large) and 20ft of Penn Plax Deluxe Silicone Airline Tubing Bubble Disk provides a continuous tower of bubbles to help aerate your aquarium Uses a standard 3/16" tubing connection High quality silicone tubing that does not crack or become brittle over time like regular tubing Silicone Airline Tubing is a Standard 3/16" diameter common to most airline accessories