Blæser Jonsbo FR-505B

The Jonsbo FR-505B is a 120 mm computer case fan engineered for balanced airflow and low acoustic output. With a rotational speed range from 800 to 1800 RPM and a maximum airflow of 47.2 CFM, the fan is intended to maintain stable temperatures in desktop systems while remaining visually neutral in black-and-white finishes. Its design focuses on delivering effective heat dissipation for components such as CPUs, GPUs, and system enclosures without introducing excessive noise.

Advantages

The fan combines a wide operating RPM range with moderate maximum airflow to suit varied cooling demands. Low noise figures — 13.3 dB at the lower end and 30 dB at the upper end — help preserve a quiet environment during light workloads while providing increased cooling when needed. The 120 mm diameter provides compatibility with most standard case mounts, and the two-tone colour scheme allows for discreet or accent installation depending on system aesthetics.

Suitable for (tasks / use cases)

• General case ventilation for desktop PCs
• Supplemental intake or exhaust fan in mid-tower and full-tower enclosures
• Cooling for systems with moderate thermal loads: office PCs, media centers, and mainstream gaming rigs
• Replacement or upgrade for existing 120 mm fan mounts

Key specifications

• Fan diameter: 120 mm
• Rotational speed: 800–1800 RPM
• Maximum airflow: 47.2 CFM
• Acoustic level: 13.3 dB (low) — 30 dB (high)
• Colour: black and white

How to use

Mount the fan in a compatible 120 mm case location using the supplied or standard mounting screws, ensuring the airflow direction matches your case ventilation plan (intake or exhaust). Connect the fan to the appropriate motherboard fan header or fan controller, observing the correct connector type and voltage control method supported by your system. Verify that cables are routed away from moving blades and other sensitive components before powering the system. Adjust fan speed through BIOS/UEFI settings or a fan controller to achieve the desired balance between cooling performance and noise.

Recommendations

For best thermal results, position the FR-505B to create a consistent airflow path through the case, pairing intake and exhaust fans where possible. Regularly inspect and clean the fan blades and surrounding filters to maintain airflow and acoustic performance. Use motherboard or software fan curves to limit maximum RPM in quiet environments and allow higher RPM under heavy loads.