A standard system can be opened from the front or rear and is therefore supplied with an extra stable wide trolley for both ends.  In between, subject to height and length of the vehicle, one or more narrow trolleys are fitted. 

The trolleys, run on synthetic wheels with self lubricating bearings and, are connected diagonally with a system of struts. The strut system ensures that the complete superstructure stays together and that the tilt is folded when opening. 

When opening from the front is not a requirement, the front trolley is deleted which has an influence on the tare weight, and the measurement of the folded system.