File folder for keeping of documents, has two rigid covers, rigid mount, and unit that is arranged between covers for fixing file folder contents, where active retaining mechanism is arranged on inner side of rear covers
DE102005036737A1
Transportation unit, has switching unit actively and simultaneously switching direction indication and warning indication or vice versa during determination of towing situations in constant predetermined ratio
DE102005012679A1
Method for operating a surface cleaning head and surface cleaning head for performing the method
