Manufacturer page.

The Classic 4000 belongs to the Individual series and is among our most exclusive and ergonomically advanced chairs. It features a knee-tilt mechanism and a backrest with four elastic bands adjusted to your natural spinal profile, providing maximum support and relief. The unique kneetilt mechanism, in combination with the Dux seat, creates a balance that significantly enhances the users freedom of movement. As muscle strain is reduced, blood circulation is also improved, helping you stay alert and focused for longer periods. The Classic 4000 is available with a high or medium-high back and can be adjusted for individuals with back issues or existing back injuries. Perfect for those with specific needs, ensuring that your chair is always properly set up for you.