Aquarium Air Stones / Air Diffusers / Bubble Stones {6 pack}, model# 1112-6; manufactured by Bubblemac Industries, Inc. High-Quality Aeration Products. **MADE LOCALLY, USED GLOBALLY!** These Bubblemac design air diffusers have been time tested in fisheries and college labs worldwide over the past 30+ years. Machined from a solid plate of 100% Glass-Bonded Silica, these diffusers are far superior to anything currently available on the market. Don't waste another dollar on the blue air stones which seem to dominate the market today! These High-Quality Air Diffusers Will Last A Long Time! Bubblemac Air Diffusers are Proudly Made In The USA, Durable, Affordable and Easy To Maintain! This may not be the LAST air stone you buy, but you can count on it being with you for a while! Diffusers Measure: .75" x .75" x 1.5" and come with a 5/32" air line connection {Suggested CFM= .10 or 3 lpm} - Making these air stones compatable with most low cost air pumps. Simply plug it into your airline and "Watch The Bubbles". 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, SERVICE LIFE UNLIMITED when used in pH of 8.0 or less. ALL Bubblemac Products Come With A No Questions Asked Return Policy! If you do not agree that our diffuser designs "Outperform" the others "Hands-Down," Simply Return The Product For A Full Refund! Safe for Fresh or Salt Water. Proper aeration promotes healthy fish and plants by increasing circulation, adding oxygen and "eliminating dead spots" in your tank. -- "Made Locally / Used Globally" --