My husband and I were in the market for a new mattress and are just thrilled with this Silver BRS900-C Extra Firm mattress from Beautyrest.  This mattress is beautifully constructed to last for years of restful sleep.  It offers the best back support I have ever found, and I no longer wake stiff and with back pain.  It is ultra firm, offers edge support, a cover design that keeps sleepers cool and comfortable, and low motion transfer so you are not wakened by a partner's movements.  The mattress is more than 12 inches deep with the plush, soft top.  I have been thrilled at the good restful sleep I have had with this mattress, and it has been the best thing for my back.  Absolutely would purchase this mattress again and definitely recommend it for anyone that loves super firm support for sleeping.