Double Panel Sliding Plug Door  Drive Unit The central electric drive of the 2-leaf sliding plug door (SST-E-Z) is provided in the form of a direct current motor, which generates the door movement by means of planetary gearing, the guide elements and a synchronous belt drive. The guide elements of the right and left-hand door leaf are installed as mirror-images of each other and describe opposite movement paths. The door path is divided into - Swinging movements of parallel link system - Moving the roller carriage on guide tubes. For the 2-leaf SST-E-Z with a portal width of approx 1600mm, this ensures a clear entrance of 1300 mm.