A storage cage — also called a warehouse cage, butterfly cage, warehouse cage bin or turnover iron cage — is a standard logistics container mainly used to hold and move large items. Stackable storage cage: pairs with forklifts, lifts and cranes, stacks four high for a vertical warehouse; uniform sizes and fixed capacity show contents at a glance and make in-warehouse counting easy; contact-welded from high-tensile wire, with a firmly welded U-channel steel bottom. Stackable butterfly cage: empties fold flat to use space well; the front of the cage opens to reach goods. The cage uses Q235 high-carbon rod as raw material, cold-drawn into sections. Mesh pitches are typically 50×100, 100×100 and 50×50, spot-welded into half-finished panels. Panels are then galvanized or powder-coated (most cages are galvanized), and assembled into finished units. The main material is high-tensile wire drawn from rod, typically 5mm, 6mm or 6.4mm; the bottom is welded U-channel, rolled on a cold-rolled strip mill, with the four bottom corners stamped in one operation. Heavy-duty cages work like regular ones: both fold and stack. A foldable cage usually outlasts a plastic tote and carries more; welded from wire mesh, it holds more than a typical returnable bin.