The AC 4 chair, Vitra

The AC 4 chair from Swiss manufacturer Vitra. The base is made of metal. The back is divided into three sections: the lumbar supports your lower back, Flex zone to support the upper back and the section with the strongest support in the shoulder area. The model has the following: seat depth adjustment, synchro-mechanism, automatically adjust the elasticity of the backrest under the weight of sitting, adjustable armrests in height, width and tilt, adjustable seat height with gas-lift.