1Ball bearings in the wheel frame, silent, long life time. 2Stainless steel screws, rust corrosion resistance. 3The pump head designed for easy disassembly, easy to clean and maintain. 4The direction of stream of the peristaltic pump depends on the connection way of positive and negative. 5Suitable for aquarium, chemicals, liquids and other dosing additivesFeatures: Ball bearings in the wheel frame, silent, long life time. Stainless steel screws, rust corrosion resistance. The pump head designed for easy disassembly, easy to clean and maintain. The direction of streamof the peristaltic pump depends on the connection way of positive and negative. Suitable for aquarium, chemicals, liquids and other dosing additives Specifications:Tube material: Transparent silicone tube Shell material: PC Rolling wheel: POM Roller type: Ball bearing Motor: 12V DC motor DC motor current: 0.5-1.4A Stream range: 0-400ml/min Tube inner diameter: 6.4mm / 0.25inch Tube outer diameter: 9.6mm / 0.38inch Wall thickness: 1.6mm / 0.06inch The maximum diameter: 9.6mm / 0.38inch Working temperature: 0-40 Relative humidity: 80% Weight: Approx. 273g Package Included: 1 x High StreamPeristaltic Pump 1 x Hex Key Note: Please allow small size error due to manual measurement. Thanks for your understanding. Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.