Feature: Imitation of natural water flow, 360 ° rotary design, can create rotating in fish tank. Free of power, large flow, can increase the contact between water flow and air, increase the oxygen content in water. Quick disassembly and easy cleaning. Made of good quality plastic, non-toxic and durable, safe to fishes. Help make fish more active and healthy. Spec:Material: PlasitcColor: BlackOptions: 25mm, 32mmSize: 25mm: length 4.5cm/1.77inch, width 3.4cm/1.34inch, outer diameter 2.9cm/1.14inch, inner diameter 2.5cm/0.98inch32mm: length 5.6cm/2.20inch, width 4.2cm/1.65inch, outer diameter 3.5cm/1.38inch, inner diameter 3.2cm/1.26inchPackage list:1 x Flow maker