The MTC4PF with battery is a MattzoTrainController with an integrated, rechargable battery.
The dimensions equal the size of a standard LEGO battery box (8×4 studs = 64mm x 32mm). It has an on/off switch, a status LED, two plugs for LEGO Power Functions train motors, and several connectors for LEDs or other appliances. The battery can be charged via USB.
The MTC4PF with battery was designed by our former core development team member Thorsten. He has also compiled building instructions (in German) and created STL files for the case.
Instructions and STL files are available for download here.