Genuine Herman Miller Aeron Classic Size B complete mesh seat-back assembly with adjustable lumbar support. This listing is for the entire seat-back assembly shown in the photos, including. Herman Miller Size B seat-back frame. Adjustable lumbar support attached to the back. The frame is marked Herman Miller and 167029. Good used condition with normal signs of previous use and storage, including some cosmetic scuffs, marks, dust, and wear. The mesh appears to be in good overall condition with no major tears noted. This is a genuine Herman Miller OEM assembly and is a great replacement for an Aeron Classic with a damaged frame, worn mesh, or missing lumbar support. Please review all photos carefully for exact condition and verify compatibility with your specific Aeron chair before purchasing. You will receive the complete mesh seat-back assembly with attached adjustable lumbar support exactly as pictured.