The warehouse cage is a common logistics container in today's plants, used for storage and turnover in warehouses and workshops. It is welded from cold-drawn wire with a welded U-channel steel bottom, and is often called an iron frame. Four styles are common: First, the foldable cage, in regular sizes of 0.8m, 1m and 1.2m, usually kept in stock. Second, the wheeled cage, with casters on the bottom — typically two swivel casters and two rigid casters with brakes — used on the factory floor to move around freely on flat ground. Third, the rack-mounted cage, built from square tube in a special I-like layout, similar to a pallet, that sits directly on racking — a best-seller. Fourth, the hollow-board-lined cage, with hollow board lined on five sides to cushion the inner product and stop it from falling. Whichever style, the cage folds flat when not in use, effectively cutting the space it takes in the warehouse.