That’s the one that carries the most. You can easily tow two or three RollTainers behind each other and then you can move six times the quantity you usually move with a Rolly. Because of the arrangement of fixed and movable casters the "six at one time" RollTainer runs like on rails.

And if you don’t need them at the moment: you can reduce the storage space. Just pull out the front frame and put it beside the back one. Now you can easily stack the RollTainers one on top of the other.