Marklin's Z scale locomotives run on fewer volts and less amperage than N, HO, O and larger scale's locomotives. Using anything but power packs rated for Z scale will damage the small motors. Output voltage is rated for 11 volts at 1 amp for locomotives and 11 volt at 1.6 amps for accessories. One pair of terminals power the track and the other pair power the accessories. The size of the case is about half the size of a typical power pack used for other scales. The dial is smooth and will run the locomotives in FORWARD and REVERSE. This model power pack includes the 120 volt wall plug power adapter. My Marklin locos run at very slow speeds with this power pack, which I prefer, but will fly around the track at top speed when the dial is at full throttle. This is my second power pack as I required two for my Z scale model railroad. It's is worth every dollar and will save you from spending hundreds of dollars on new locomotives or paying costly repairs. This is a must have for Z scale.