EK-Vardar EVO is industrial grade high-static pressure computer cooling fan, designed and built primarily for highest-performance computer liquid cooling systems. Developed in-house and first introduced in 2014, renowned EK-Vardar fans have now evolved into new EK-Vardar EVO lineup. EK-Vardar EVO fans with Extended range (ER) of PWM operation feature a special Start-Stop function which brings a true 0db experience for the absolute silent fan operation. EK-Vardar EVO is simply the best choice for computer radiator cooling as it provides unmatched performance throughout the entire operating range.The Vardar family of cooling fans carries the name of a type of the cold northwesterly wind blowing from the mountains down to the valleys of Macedonia. It is a type of ravine wind, enhanced by a channeling effect while blowing down through the Moravia-Vardar gap, bringing cold conditions from the north to the Thessaloniki area of Greece. Most frequent during winter, it is blowing in the rear of a depression when atmospheric pressure over eastern Europe is higher than over the Aegean Sea.The key characteristics of EK-Vardar EVO fans are:High-static pressure / low noise profile - unlike other general-purpose computer cooling fans, the EK-Vardar family of fans is built specifically for computer liquid cooling systems, namely radiator cooling. The 7 fan blade design is optimized for high-pressure operation while maintaining the low noise profile throughout the whole operation range of the fan. Vardar\'s design and construction are also very suitable for high-performance air coolers or as case fans for restrictive cases with dust filters.High-quality motor and bearing assembly - New electrical design, actively cooled motor windings and Hydro-Dynamic bearing with 50.000 hours life span (MTBF) ensures uninterrupted operation for years to come. Precise Pulse Width Modulation (PWM) for fan speed adjustment allows performance on demand. EK-Vardar EVO ER models feature hydro-dynamic bearing which is superior to double-ball bearing due to less friction, wear and vibration and consequently less noise.Sealed-edge fan casing - The classic, yet effective square shape of the fan casing provides optimal performance in either pull- (suction) or push (pressure) regime without hydraulic losses thus ensuring the optimal cooling capacity of your liquid cooling radiators. The classic shape of the fan frame also allows easy cable routing while grouping more fans on one radiator.0db regime - EK-Vardar EVO features a unique Start-Stop function which ensures the user a true 0db noise environment. If the PWM curve is set so that the PWM duty cycle is below 25-30% PWM (depending on motherboard model and fan model) this fan will simply stop spinning. If the PWM duty cycle is raised by the fan control software, the fan will spin up once again. This feature is very useful for preventing radiator dust buildup in idling PCs and to prolong the lifecycle of the fan itself.Timeless design - the EK-Vardar EVO fan fits subtly into any liquid cooling computer without drawing too much attention. Delivered in all black color scheme it blends perfectly with a sleek and minimalist looking EK-CoolStream liquid cooling radiator.Specifications: - Maximum speed: 2200 RPM (+/- 10%)- Rated Voltage: 12V DC- Power Draw: 2.16W- PWM Duty Cycle: 25-100% - ER (Extended Range)- Connector: 4-pin PWM header- Shaft bearing: Hydro-Dynamic bearing- Bearing durability: 50.000 hrs @ 40C (MTBF)- Dimensions: 120 x 120 x 25 mm- Max Air Flow: 77 CFM = 131 m/h- Static Pressure: 3.16mm H2O = 31 Pa- Sleeved cable length: 300 mm- Noise Level: 33.5 dBAContents: - EK-Vardar EVO series fan- Self-tapping screws (4 pcs)