Fortis PI 400 | Back Care Office Chair
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The Fortis PI 400 | Precision Ergonomic Office Chair
The Fortis PI 400 is a high-performance ergonomic chair engineered to deliver precise support, exceptional adjustability, and long-lasting comfort in demanding work environments.
Why Choose the Fortis PI 400?
Developed with a focus on advanced ergonomic performance, the Fortis PI 400 is designed to adapt to your body with precision. Every adjustment point works together to support healthy posture, reduce strain, and enhance comfort throughout the working day.
Its intelligent design promotes optimal spinal alignment while helping to minimise fatigue, making it ideal for both office and home workspaces.
Precision Comfort, Fully Adjustable
The Fortis PI 400 is built for users who need more than basic adjustability. It offers a fully customisable seating experience, allowing you to fine-tune every element of your chair:
Height and angle adjustable headrest for neck support
Height and independently adjustable backrest for tailored spinal positioning
Seat depth and angle adjustment for proper thigh support
Pneumatic lumbar pump for targeted lower back support
4D adjustable armrests for complete arm and shoulder alignment
Italian synchronised mechanism with multi-position lock and fast tension control
This level of adjustability ensures the chair fits you — not the other way around.
Designed for Movement and Support
The synchronised mechanism encourages natural movement while maintaining support, helping reduce stiffness during long sitting periods. With multiple locking positions and responsive tension control, the Fortis PI 400 supports both active and static sitting styles.
Built for Performance and Durability
Constructed with premium materials, the Fortis PI 400 is designed to withstand intensive daily use:
High-density PU moulded foam for consistent comfort and pressure distribution
Class 4 gas lift for heavy-duty reliability
700mm aluminium alloy base for strength and stability
60mm hard brake castors for smooth, controlled movement on all floor types
Fighter Black fabric (130,000 Martindale) for exceptional durability
This is a chair built for long-term performance in professional environments.
Certified for Professional Use
The Fortis PI 400 meets rigorous European and international standards:
EN 1335-1:2020 & EN 1335-2:2018 for safety and dimensions
BS 5459-2 certification for 24-hour use
Tested for durability, stability, and component strength
Maximum user weight: 150 kg
These certifications ensure reliability, safety, and suitability for intensive use.
Designed to Solve Everyday Discomfort
If you struggle with:
Lower back discomfort
Poor posture from static sitting
Limited adjustability in standard chairs
Fatigue during long working hours
Chairs that wear out quickly
The Fortis PI 400 provides a professional-grade solution focused on long-term support and adaptability.
Work Better. Sit Smarter.
Whether in a corporate office or home setup, the Fortis PI 400 delivers the support, flexibility, and durability needed for modern work.
Available now from KOS Ergonomics.
Upgrade your workspace with precision ergonomic support.
Posture Tips & Improved Ergonomics
Sitting for long periods can often lead to discomfort or pain, especially in areas like your hips, lower back, and tailbone. Here are some simple, effective tips to help improve your posture and reduce common issues like hip pain when sitting, lower back pain when sitting, and tailbone pain when sitting.
1. Support Your Lower Back
If your lower back hurts when sitting, it's often due to a lack of proper support. Make sure your chair has good lumbar support to keep your spine aligned. You can also use a small cushion to provide extra support if needed.
2. Keep Your Hips at the Right Angle
When your hip hurts when sitting, it may be due to poor alignment. Your hips should be level with or slightly higher than your knees. Adjust your chair height so your feet are flat on the ground and your knees form a 90-degree angle. This can help reduce hip joint pain while sitting and prevent buttock pain when sitting and lying down.
3. Adjust Your Seat Position
For those dealing with coccyx pain when sitting or a sore tailbone from sitting, ensure your seat isn’t pressing too hard on your tailbone. Try a cushion with a cut-out section to relieve pressure on the tailbone and improve comfort.
4. Move Regularly
If you feel buttock ache when sitting or hip discomfort when sitting, it's a sign that your body needs a break. Stand up, stretch, or take a short walk every 30-60 minutes. Regular movement can ease tension and prevent hip ache when sitting or lower back pain while sitting.
5. Exercise for Strength and Flexibility
A good workout for back pain can strengthen your core and back muscles, reducing discomfort. Exercises like gentle stretches or yoga can help relieve bottom pain when sitting, butt pain while sitting, and improve overall posture.
By following these posture tips and incorporating ergonomic tips into your daily routine, you can reduce discomfort and improve your overall well-being while sitting. Make sure to listen to your body and adjust your workspace as needed to stay comfortable throughout the day.
Download Your FREE Posture Watch Poster!
Get Serious About Your Posture With This Helpful, Free Reminder!
Armrest Height: 66 - 90 cm
Backrest Height: 74 - 88 cm
Backrest Width: 44.5 cm
Total Width: 72.5 cm
Seat Width: 52.5 cm
Total Depth: 65 cm
Seat Depth: 41 - 47 cm
Base Diameter: 72 cm
Weight: 28.8 kg
Fabric Abrasion Resistance: 130,000 on Martindale test
Max User Weight: 150 kg
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