The aluline double dog crate is an aluminium plastic composite transport box in xxl size it is a safe and comfortable way to transport larger dogs when travelling by car it comes with a variable partition which can be inserted to create 2 smaller areas if you are transporting 2 small dogs there is a track on the roof of the box where partition is inserted it is then attached to the front of the box with three screws this means that when the partition is not in use there is no track on the