Strobel Organic Strobel-Fold Foundation, Folds in Half to Move Easily Twin For Strobel mattresses or any mattress. Unique patent pending design folds in half and compresses, then opens flat and expands for sturdy box spring use. No assembly required. A solution for tight space hallways and stairways, and easier moves. Neutral upholstery goes with any mattress Made in USA by Strobel For Strobel mattresses or any mattress. Unique patent pending design folds in half and compresses, then opens flat and expands for sturdy box spring use. No assembly required. A solution for tight space hallways and stairways, and easier moves. Netural upholstery goes with any mattress Made in USA by Strobel