1、The direction of flow of the peristaltic pump depends on the connection way of positive and negative. 2、Ball bearings in the wheel frame, silent, long life time. 3、The self‑priming viscous pump head designed for easy disassembly, easy to clean and maintain. 4、This vacuum pump is suitable for aquarium, chemicals, liquids and other dosing additives. 5、Simple design, easy to install, convenient to use. Features: 1. The direction of flow of the peristaltic pump depends on the connection way of positive and negative. 2. Ball bearings in the wheel frame, silent, long life time. 3. The self-priming viscous pump head designed for easy disassembly, easy to clean and maintain. 4. This vacuum pump is suitable for aquarium, chemicals, liquids and other dosing additives. 5. Simple design, easy to install, convenient to use. 6. Can be equipped with constant speed DC geared motor, stepper motor (adjustable speed) and synchronous motor, long motor life, low noise stepper motor. Specification: Condition: 100% Brand New Item Type: High Flow Peristaltic Pump Working voltage: 6~30V Working Environment: 0-40 Relative Humidity: 80% Medium Flow: the flow direction of the pump depends on the positive and negative connection Flow Range: 0 - 400ml / min Tube inner diameter: 6.4mm / 0.3inch Tube outer diameter: 9.6mm / 0.4inch Wall thickness: 1.6mm / 0.06inch Maximum Diameter: 9.6mm / 0.4inch Tube Material: Transparent silicone tube Shell Material: PC Roller: 304 stainless steel wheel frame Roller type: Ball Bearing Pump Cover: Hand screw, quick release for easy tube replacement Package List: 1 * Peristaltic Pump 1 * Hex Wrench Note: 1. Please allow slight error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.