S-FLOW fan blade design delivers 30% higher airflowHigh performance and PWM auto speed controlHigh performance 12cm fan with S-FLOW blades supplying 30% more airflow than a standard fan at the same speed. The greater performance combined with PWM automatic speed control allows the fan noise to be kept to a minimum.The Viper fan creates more focused airflow providing blind-spot cooling, which makes it an ideal solution for a case or heatsink fan. HDB (Hydro Dynamic) bearings extend fan life and further enhance noise reduction.Hydro Dynamic Bearing structure advantage:HDB uses a dynamic pressure field and an anti-leak seal to maintain constant bearing lubrication, extends fan life up to 50,000 hours and lowers fan noise.- High performance 12cm Viper Black fan- S-FLOW fan blade design delivers 30% higher airflow- Super silent with PWM auto speed control- Hydro Dynamic Bearing extends fan life up to 50,000 hours