The KALLI DOS backrest and positioning cushion improves sitting comfort and provides an interface between the backrest fabric and the back of the person. A situation of discomfort in the back would be likely to cause the user to slide on the seat of the chair. This backrest has the following assets: • Reduce the pressure felt by the person in contact with the frame and backrest cloth at the level of the spine and shoulder blades • Marry the morphology of the person, even in case of kyphosis • Reduce areas of friction • Bring comfort to everyday life • Facilitate installation and attachment to the chair The advice of Sonia Baudry, occupational therapist DE: "I recommend the Kalli back to people with a risk of localized overpressure related to an alteration of curvature of the spine, or a tendency to tilt the trunk laterally due to a slight postural deficit . " Characteristics : • viscoelastic foam: 80 kg / m3 • Cover: Pharmatex Maintenance tips : • Saturated steam without addition of formalin, disinfectant or soapy water • Allow to air dry before putting the cover back on