Pawfly Aquarium Air Stone 4 Inch Bread, Fish Tank Air Stone Oxygen Diffuser for Air Pump Fish Tank Bucket Pond and DWC Reservoir, 2 Pack

Medium Bubbles: The air stone produces abundant dense bubbles to aerate your water reservoirs. A great way to increase oxygen solubility in fish tanks, aquariums or ponds.
Model: ASR-100; Jetting volume: 15 L/min; Recommended air pump power: > 4 W; Standard ID airline tubing: 3/16″ or 3/8″. Great for aquariums, DWC systems or ponds.
Reliable Material: Made of mineral material and sintered at a high temperature, it causes no effect to the health of your aquatics. Help keep fish or roots growing healthily.
No More Floating: Measures 4″ D x 1.5″ H and weighs 11.6 oz. And its wide and flat bottom always keeps it sitting stably in the tank to produce steadier bubbles.
Easy to Use: Soak the stone completely in water for more than 3 hours before use. Clean it regularly with a brush as it gets clogged after weeks or months of usage.