Air Stones / Air Diffusers / Bubble Stones / Aerators For Aquariums - {10 pack} - Bubble Stones manufactured by Bubblemac Industries, Inc. -100% Glass-Bonded Silica Air Diffusers. {Self-Weighted} -- Bubblemac Air Diffusers are machined from a solid plate of Fine Pore Silica creating the Highest-Quality Bubble Stone on the market today! Have you tried the "blue import" airstones that "go-away" in a short time? These Diffusers are Durable, Low Maintenance . Made in the U.S.A. "These air diffusers ARE NOT Discard-A-Stones, they last a long time!" High-Quality 100% Glass-Bonded Silica Air Diffusers hand-tooled in our Central Florida factory. Diffusers each measure: .5" x .5" x 1.5" with a standard 5/32"" barb air line connection. Aeration Promotes Healthy Fish and Plants by increasing circulation, adding oxygen and eliminating "dead spots" in your tank. *Don't Forget: Your plants, fish and other living organisms need oxygen to flourish. Bubblemac air diffusers have the highest dissolved oxygen transfer ratio of any air diffuser on the market today!* Safe for Fresh or Salt Water. Commonly used in College Laboratories these bubble stones produce a uniform medium bubble. "Ya'll Got Bubbles"? -- SPECS: 100 % Glass-Bonded Silica, Maximum Pore Size 140 Microns, Nominal Partical Retention 50 Microns, Flexural Strength 2500 PSI, Bubble Size 1-3 MM, UNLIMITED LIFETIME When Used in pH of 8.0 or Less!