Versatile JARKE Airector Portable Stacking Racks combine the unit load capabilities of a pallet with the product protection and positive alignment of stacking posts. Constructed of heavy-gauge tubular steel, units may be stacked 4 high to utilize air rights with high-density storage. Four-way entry allows maximum accessibility of materials to be shipped or stored. 4-1/2" underclearance. Available with 1x6" sturdy decking or without. Build your own racks from components listed below or order complete units that include (4) stacking posts, (4) sockets and base frame. 1x6" sturdy deckboards used on models with deck. Socket: 2-1/2" square.NOTE: Bases and posts are sold separately. Must order both bases and posts to build a complete rack.