Medium bubbles: The air stone disc produces dense and abundant bubbles. A great way to increase oxygen solubility in your aquarium and support aquatic life. Model: ASD-040; Jet volume: 2 L/min; Recommended air pump power: 2W - 4W; Standard air tube ID: 0.5cm. Suitable for use in aquariums, fish tanks, and small ponds. Reliable Material: Made of mineral material and sintered at high temperature. Ideal for aeration in a DWC tank. Helps maintain healthy fish and root growth. Stable in Water: Each disc measures 4D x 1.8H (cm) and weighs 28.3g. Its round, flat shape allows it to sink to the bottom and remain securely in place. Easy to use: Soak the stone completely in water for 1 hour before first use. Clean regularly with a brush, as it may clog after weeks or months of use.