Safco® Mobile base for mixx modular storage cubes Mobile Base for Mixx™ Modular Storage Cubes, Black, 15w x 15d x 4h Create your own unique storage and filing system with interlocking storage cubes. Cubes stand alone or can be arranged to best suit your organizational needs. All cubes interlock top-to-bottom and side-to-side. Add mobility with Mixx™ Optional Mobile Bases (SAF5346/SAF5347), sold separately. 5/8" thick panels are fully finished on all surfaces, with PVC edge-banding on all exposed ends for increased durability. Quick-lock fasteners make assembly easy.