Small Air Stone Ball: Each airstone measures 2" in diameter and weighs 3.6 oz. Tiny but well-constructed for continual bubbling. Ideal for small fish tanks, DWC systems or small ponds. Medium Bubbles: The air stone balls produce a good amount of dense bubbles. A great way to increase oxygen solubility in your aquariums and enliven the aquatic lives. Model: ASR-050B; Jetting volume: 5 L/min; Recommended air pump power: > 4 W; Standard ID airline tubing: 3/16" or 3/8". Efficient aquarium bubblers for constant air diffusion. Reliable Material: Made of mineral material and built solidly, it causes no effect to the health of your aquatics. Help keep your fish or roots growing healthily. Easy to Use: Soak the fiah tank air stone completely in water for 1 hour before use. Clean it regularly with a brush as it gets clogged after weeks or months of usage. The 2 inch air stone balls feature durability, steady bubbles and high dissolved oxygen rate. Optimal for aerating your water reservoirs and livening up your aquatics. A necessity to have in the house of aquatic lovers.