Believe it or not, we've made the box spring more functional, more durable, and dare we even say, fun! Our No Assembly Box Spring is not your average foundation. Its folding design not only makes set-up insanely easy, but it also comes in handy on moving day, maneuvering easily in and around tight hallways and corners. What's more, it features a structure made of thick and durable steel, meaning that frames and mattresses may come and go, but this box spring will be with you for the long haul. Once unboxed, this brilliant foundation practically assembles itself by taking shape once unfolded. Essentially, deciding where to place the bed will take longer than setting up this box spring. Backed by both our 5-year worry free warranty and hundreds of positive customer reviews, this box spring is about as easy as decisions get. Size: california king. Material: Metal.