EcoBox 18 x 24 Inches #40 Instapak Quick Room Temperature Bags, 1 Bag (E-2031-1) The ultimate protection for your fragile shipments. Chemical reaction that causes expansion of the foam is activated simply by the touch of your hands in room temperature. No messy clean ups, plugged nozzles, or loose parts. Recommended box size for expansion: 12" x 12" x 12". 1 bag sold per purchase.