Brand new in box, unassembled, SIHOO M57 Ergonomic Office Chair, Mesh Back Desk Chair with 3D Armrests

• ADJUSTS TO YOU, FROM BOTTOM TO TOP - Whether you're working, gaming, or just relaxing, SIHOO ergonomic chair adapts to your needs. The headrest tilts and lifts to support your neck just right. The lumbar support shifts in height and depth to fit the curve of your lower back. Recline from 90° to 126° to change posture throughout the day. With smooth height lift and 360° swivel, you move freely and stay comfortable—however you sit.

• ERGONOMIC SUPPORT WHERE YOU NEED IT MOST - Recommended by the Ergonomics Application Association, the SIHOO ergonomic office chair is shaped to match the natural curve of your spine. The split backrest cushions your back and helps relieve pressure along the spine. The waterfall-edge seat supports your thighs while improving circulation, keeping you comfortable through long hours at your desk.

• STABLE, DURABLE, AND QUIET - Built with a reinforced aluminum base and a dual-frame backrest, our desk chair holds up to 330 lbs with ease, staying sturdy and supportive even with daily use. Smooth-rolling, silent casters glide across the floor without noise or scratches—perfect for quiet workspaces.

• CERTIFIED SAFETY YOU CAN TRUST - Every key part of the SIHOO chair has undergone over 100,000 rigorous safety tests and is certified by BIFMA and SGS. Built with your safety in mind, it offers the confidence to sit, recline, and move freely—knowing your chair is tested, trusted, and made to last, perfect for long workdays, gaming sessions, or everyday comfort at home.