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Black 80mm square-frame case fan with curved blades, 4-pin PWM connector

Cooler Master

Cooler Master SickleFlow 80 V2 MFX-B8NN-25NPK-R1 80mm case fan

SKU CH-J7FS-17DKF MPN MFX-B8NN-25NPK-R1

An 80 mm PWM case fan with a revised blade curve, reinforced frame and sealed bearing for 650–2500 RPM airflow up to 30 CFM at 6–25 dBA

  • Fan size80 mm
  • Number of fans1 Fan
  • Fan controlNo Controller
  • Fan depth25 mm
  • Bearing designRifle
  • Rotational speed650–2,500 RPM +/- 5%
  • All-black design fits stealth builds
  • Revised curve blades boost airflow and pressure
  • Reinforced frame cuts turbulence and noise
  • Sealed rifle bearing resists dust and oil loss
  • 4-pin PWM runs 650 to 2500 RPM

Compact 80 mm PWM fan for tight builds

This 80 mm case fan fits small-form-factor chassis and low-profile air coolers where a 120 mm unit will not mount. The 4-pin PWM connector lets the motherboard regulate speed automatically, so the fan runs only as fast as the thermal load demands. Its all-black, non-LED frame keeps the interior looking clean without added lighting.

Replaces noisy stock 80 mm fans when silence matters

Stock sleeve-bearing fans often whine above 1 000 RPM; this rifle-bearing model stays at 6 dBA at the 650 RPM floor and reaches 25 dBA at the 2 500 RPM ceiling. The jump is worth it when a build lives on a desk or in a media centre and the owner wants measurable airflow — 30 CFM — without an audible turbine. Builders who need more than 30 CFM or a larger mounting pattern should look elsewhere.

Mounts directly to 80 mm screw holes on cases

The 25 mm thick square frame aligns with standard 80 mm mounting points, so no adapter brackets are required. The reinforced ribbed frame reduces turbulent noise, while the two-tier sealed bearing resists dust ingress and oil loss for longer service life. A 4-pin PWM header on the motherboard is the only external connection needed.

How it compares

Measured against everything we stock in PC Cooling Fans, at today’s prices. Recalculated every night.

Price $9.99
Cheaper than about 91% of the 8,339 comparable items (median $19.99).
Fan size 80 mm
Lower than about 75% of the 1,114 comparable items (median 120 mm).

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Specifications

Product
Brand nameCOOLER MASTER
Product lineSickleFlow 80 V2
Model nameMFX-B8NN-25NPK-R1
Product typeCase Fan
Product colorBlack
Performance
Rotational speed650–2,500 RPM +/- 5%
Airflow rate30 CFM +/- 10%
Power
Power input connector4-Pin PWM
Size & build
Fan size80 mm
Number of fans1 Fan
Fan depth25 mm
Bearing designRifle
Product dimensions80 × 80 × 25 mm
Shipping weight0.13 kg
Package size201 × 114 × 32 mm
Compatibility
Compatible withCase & Air Coolers
Environment & compliance
Operating noise6–25 dBA
More details
Fan controlNo Controller
LED lightingNon-LED

Questions about this item

Will the 80 mm square frame with 25 mm thickness fit my case or cooler mounting holes?

The fan measures 80 x 80 x 25 mm, matching the standard 80 mm mounting pattern used on most cases and air coolers.

How do I connect the 4-pin PWM cable so the motherboard controls speed between 650 and 2500 RPM?

Plug the 4-pin PWM connector into a motherboard PWM header; the board will then vary voltage to keep the fan within the 650 – 2500 RPM range.

Does the sealed rifle bearing need lubrication or replacement after extended use?

The two-tier sealed bearing is designed to prevent oil leakage and dust ingress, so no user lubrication or bearing replacement is required.

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