Pond,Water Gardens, Aquaponics, Hydroponics, Aquarium Air Diffuser/Air Stone {AS15S} - Manufactured by Bubblemac Industries, Inc. - 100% Glass-Bonded Silica Air Diffusers Bubblemac Air Diffusers Have Been "The Standard Of The Industry" In Fish Farms, Hatcheries, College Labs and Lake Restoration Projects Worldwide For 30+ Years. This Diffuser Design Will Outperform Any Other Air Diffuser On The Market Today! - MADE LOCALLY / USED GLOBALLY - 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 of 8.0 or less. Made In The USA. Machined and Hand Tooled From A Solid Plate Of Silica, Bubblemac Air Diffusers Are Durable, Efficient, Effective and Affordable. This diffuser measures 1.5" x 1.5" x 6" and has a 1/4" OD air line connection. - Self-Weighted Design. - {Suggested CFM = .50 or 14 lpm} RISK-FREE OFFER: Try a Bubblemac Aeration Product And If You Do Not Agree That Our Air Diffusers Are More Durable, Require Less Maintenance and Outperform The Others "Hands-Down," --- Simply Return The Product For A Full Refund! Whatever your Application {Koi Pond, Hydroponics, Aquaponics, Water Gardens or a Large Aquarium} this Bubblemac Air Diffuser Will Increase Surface Agitation, Accelerate Oxygen Replenishment and Help Remove Harmful Carbon Dioxide. {Search: Bubblemac 6" medium pore Air Diffuser on U Tube for video}