A friend gave me my first Office Master chair, in 2006, and I am still using it this very moment! It is the most comfortable chair I have ever used, and I used it for many years with damaged arms that I used electrical tape to hold them together. My beloved wife has been “encouraging” me to buy a new chair, but I cannot bear to part with this chair so I thought I would see if I could fix the arms better, or buy new arms. Fortunately, it was easy to find the Office Master brand name still legible, so I googled for the company and found my chair model and then I found the replacement parts section and the original KR21 arms. Interestingly, there are many arms that would fit this chair, some with 4D adjustment (closer/further, forward/backwards, up/down, and tilt). My choices went from the original 1D, 2D, 3D or 4D as described previously nd I wanted the 4D, of course since I got the chair for free why not spend $150 to make it even better? Unfortunately, some of the web pages details seemed to suggest that the price was for each arm. So I thought the original K21 arms have been excellent for all these years (and we prefer a frugal and humble lifestyle) so I purchased two K21 arms for $90 plus shipping (trusting that Office Masters would give one left arm and one right arm. My replacement arms arrived about a week. As I recall, Office Masters actually delivered on Sunday! I was both surprised and so very happy! I opened the box and I observed TWO sets of KR21 arms! I only needed one set of KR21 arms ($45). So, I wrote to Office Masters customer service and explained the confusion caused by their web pages (I included a link to the very page) and they wrote me back! In fact, they gave me the refund for the extra set of arms AND they said I need not send them back the extra set of arms. I am still amazed by the integrity of this company and the amazingly fair price of their replacement KR21 arms ($45) as I was very willing to pay $90 for those KR21 arms. My only regret is not buying the 3D or 4D arms for $70-$150 for a pair of these high quality arms 3D or 4D would be so worth it. I really am an Office Masters customer forever! Thank You so much for being honorable and for manufacturing true highest quality !