Open top containers are available in various sizes such as 20ft and 40ft lengths. They are usually wrapped with tarps on top to protect goods. These containers are meant for items which are packed by crane from the top or for items too large in length for a standard container. Ideally, open top containers are the best choice for loose or bulk storage Flat rack Containers are also available in 20 and 40ft lengths. The ends of flat rack containers are either fixed or collapsible. These containers are usually used for oversize items such are trucks or large machinery.