The Mirra® Basic Chair in Shadow/Shadow: No adjustment needed for this chair's superior back support. The pliable, elastic TriFlex back supports the entire spine and conforms to size, posture, and movements. A camber shape at the base of the back gives healthful, comfortable support to the lower back below the beltline. Features Harmonic tilt that creates pivot points at the hip, knee, and ankle to allow easy and natural movement. AireWeave suspension provides custom seat comfort. This elastomeric suspension seat follows the contours of the body, distributes pressure evenly, and provides aeration.