Beautyrest Black Cal King Size Low Profile Box Springs Brand new Includes ten Year Warranty, Sleep in comfort with our Simmons Beautyrest Black Triton Box Spring Foundation nine Inch that provides stable and strong support for all Beautyrest mattresses. This standard profile foundation helps prevent sagging and bowing for the life of the mattress when used with a supportive bedframe. It's constructed with high grade wood and steel struts featuring an exclusive center Power Beam to reinforce the span in the middle of the foundation. Matching Box Spring For Collections - Beautyrest Black, Boxspring Foundation For The Mattress of yours, Low Profile 5.5 Height, Matching Black Color, Center Power Beam, High Grade Wood Steel Strut Construction, Provides Superior Support For all Mattresses, Extends The life Of your respective Mattress