Made from plywood and exempt from ISPM-15 import/export regulations, Quick-Crates are certified by US Army Defense Ammunition Center for transportation of live ammunition (4,000 lb/crate). They are intended for automotive and aerospace applications, when products must be loaded/unloaded on assembly line, as design allows full product access from top or any side. To optimize space utilization, crates can be stacked when in use or collapsed to 9 in. high when not in use.