Aquarium / Water Gardens - Air Diffusers, Air Stones; model# 1020TP, {AS3} {twin pack} by Bubblemac Industries, Inc. manufacturers of "The Forever Bubble Stone" -- High-Quality 100% Glass-Bonded Silica Air Diffusers; **MADE LOCALLY, USED GLOBALLY!** -- Bubblemac Air Diffusers are world renowned for the past 30 years as the most effective, most efficient form of aeration. Considered "The Standard Of The Industry" in fish farms, hatcheries and college labs. -- NOW AVAILABLE -- to consumers in designs created for aquarium, aquaponics and koi pond applications. -- "Made Locally / Used Globally" -- Bubblemac Air Diffusers Increase Surface Agitation, Accelerate Oxygen Replenishment and Help Remove Harmful Carbon Dioxide. The Inhabitants Of Your Tank Will Love This Air Stone. Air Diffusers Are A Self-Weighted Design And Measure 1" x 1" x 2" and come with a 3/16" OD barb. Compatible with most low cost air pumps. {Suggested CFM = 0.20 or 6 lpm} Air Diffuser Specs: 100% Glass-Bonded Silica, Maximum Pore Size 140 Microns, Nominal Particle Retention 50 Microns, Flexural Strength 2500 PSI, Bubble Size 1-3 MM, UNLIMITED SERVICE LIFE when used in pH 8.0 or less. See The Difference In Performance Our American Made Products Provide. -- Efficient, Effective, Affordable and Durable. Made In The USA.