This listing is for a box of 18 Uni-Supports, to form a AtticZone StoreFloor floor that is raised above the full depth of insulation in your attic. You will also need to buy Cross-Beams, Tri-Supports, flooring boards and 8 x 1.5” screws to complete your deck. You can work out exactly what you need from the AtticZone website but, for example, you need one of these boxes of Uni-Supports for an 8x8 ft or 12x12ft deck, and two boxes of Uni-Supports for a 16x16 deck, etc. Cross-Beams and Tri-Supports are available from Amazon. So are flooring boards but you can also pick these up from any DIY store. You can use plywood, OSB or chipboard and 4ft x 1ft boards are easiest to carry into an attic. They should be at least half-an inch thick, with 0.75” being even stronger.