TWIN DIMENSIONS - The dimensions of this standard twin size box spring are 74 x 38 x 9 inches. The length is 5 inches shorter than our Twin XL size. Please measure your bedframe to ensure compatibility. THE LAST BOX SPRING YOU’LL EVER NEED - Unlike a traditional box spring, the Smart Box Spring is made of solid steel that comes together in no time and is backed by our ZINUS “Peace of Mind” 5 year warranty DURABLY ENGINEERED - Durable steel is used to construct the inside framework of this foundation; twin size supports a maximum weight capacity of 350 lbs, while Full, Queen & King sizes can support up to 700 lbs THOUGHTFULLY PACKAGED - All parts, tools and instructions are packed into one compact box that ships straight to your door Worry-free 5 year limited warranty included; box spring only, a bed frame or platform bed is required to support this foundation and is sold separately