I have the Herman Miller with fully adjustable arms, height & lumbar. They too have 3 sizes S M L. Cost is a little high, upwards of $769. A good office supply store should sell them. Check out: http://www.smartfurniture.com/products/Aeron-Chair.html?utm_source=bing&utm_medium=cpc&utm_term=herman%20miller%20aeron%20chair&utm_content=Herman%2BMiller%2BAeron&utm_campaign=Herman%2BMiller%2B-%2BAeron&s_kwcid=AL!3691!10!628055390!14516029286&ef_id=UJbcAgAACR0iOBLX:20130710005950:s