Rising bubbles enhance vital aquarium aeration water movement, versatile aquarium air stone for decorative functional air bubbles Fits for 0.16/4mm inner diameter tubing, Stone Length: 4/10cm Material: Mineral Plastic. Color: Green Blue Total Size: Approx. 4.5 x 0.8 x 0.5/11.5 x 2 x 1.2cm (L*W*T); Per Weight: 1oz. /120g, Package Included: 4 x 4-inch Air Stone Bar Air Stone Bar An airstone, whose purpose is to gradually diffuse air into the tank and provide oxygen for fish to breathe, is an necessity to have around your house if your are a lover of aquatic animals. Pawfly air stones are made of high quality non-toxic mineral material. With high temperature sintering, the stones are sturdy and durable, have high dissolved oxygen rate and create even and tiny bubbles rather than a limited number of large ones. Made of high quality and harmless mineral material Create tiny bubbles rather than bigger ones Keep providing oxygen for your fish to breathe Come with 4 PCS 4 inches air stone bar What Kind of Airstone Should I Use Lets clarify basic knowledge: A bigger air stone needs a more powerful pump to produce more bubbles. Basically bigger air stones can produce more nice bubbles and theyre used for powerful air pumps. If you connect a bigger air stone to a small pump, the bubbles will be produced only at the front of the stone. Small pumps go well with small air stones while powerful pumps and small stones dont get along well. About Shapes The most common shape of this device is cylinder, however you can also find it in globe, disc, or even cube shape. The cylinder shapes can exist in many sizes and colors. Disc shapes can stay steady at the bottom of your tank, while globe ones can produce more bubbles in the same size.