SIHOO B300 Ergonomic High-Back Office Chair – Dynamic Lumbar Support & 5D Linkage Armrests

Elevate your workspace with the SIHOO B300, a premium ergonomic solution designed for professionals and gamers who demand uncompromising comfort. This chair combines advanced scientific engineering with intuitive adjustments to provide full-body support throughout the day. Whether you are tackling a high-intensity project or settling in for a long gaming session, the B300 adapts to your unique physique to reduce fatigue and promote healthy posture.

Key Benefits

Precision Lumbar Tracking:** Featuring a 40mm micro-adjustment system, the lumbar support moves with you. It offers 50mm of height adjustment and 30° of lateral tracking to ensure your lower back is always cradled, regardless of how you shift in your seat.

5D Multi-Functional Armrests:** The innovative 5D linkage armrests provide 360° rotation and a 100° flip-up design. They offer 4.5cm of height and depth adjustment, allowing you to align your elbows perfectly with your desk or flip them up to save space when the chair is not in use.

Breathable Wave-Pattern Mesh:** Engineered with high-density wave-ribbed mesh, the seat and backrest promote maximum airflow. This specialized material prevents heat buildup while providing firm, elastic support that maintains its shape over time.

Customizable Seat Depth:** The "waterfall" seat cushion features a 30mm sliding depth adjustment. This allows you to find the perfect position to reduce pressure on your thighs and improve circulation during long hours of sitting.

Extended Recline for Relaxation:** When it’s time for a break, the 135° large-angle recline and 30cm extra-wide headrest provide a stable and comfortable environment for a quick afternoon nap or a moment of meditation.

Key Specs

Headrest:** 30cm wide-format adjustable headrest.

Armrests:** 5D linkage (4.5cm height/depth adjustment, 360° rotation, 100° flip).

Recline:** 135° maximum tilt with synchronized tension control.

Seat:** 30mm sliding depth adjustment with waterfall edge.

Material:** Specialized wave-pattern high-density mesh.

Certification:** Fully BIFMA tested for safety, stability, and durability.

How to Use

Assembly:** Follow the included manual to secure the heavy-duty base and gas lift. Attach the seat, backrest, and armrests using the provided hex tools.

Lumbar Adjustment:** Reach behind the chair to adjust the lumbar height (up to 50mm) and depth (up to 20mm) to match your spine's natural curve.

Recline & Lock:** Pull the side lever to unlock the tilt mechanism. Lean back to your desired angle (up to 135°) and push the lever back in to lock the position for resting.

Space Saving:** To store the chair under a low desk, flip the armrests up 100° to clear the desktop edge.

Care & Safety

Maintenance:** Periodically check and tighten all screws to ensure long-term structural integrity.

Cleaning:** Use a handheld vacuum or a soft, damp cloth to clean the mesh. Avoid harsh chemical solvents that may damage the high-density fibers.

Usage:** Avoid placing sharp objects on the mesh surfaces to prevent snags or tears. Ensure the chair is placed on a level surface before reclining.

Notes

"40mm macro-precise lumbar tracking" ensures your spine remains aligned during every movement.