This optional extra allows you to lower the bed 13cm further down.so that the bed will meet all your requirements. If you need a lot of space for your luggage, you can use the standard height setting, but if you would like more space for sleeping and to increase the interior space to move around in, then you can use the lower height setting. In this setting, it is quite often no longer possible to have the second row of seats in the upright position. The seats will have to be folded down, which means the storage space decreases, but the space for sleeping increases. You can choose and enjoy this flexibility provided by this optional piece of kit.