Fake parametric cell for supplying energy with a power supply instead of batteries. You'll need 2 screws and 2 nuts, The stl files are designed for M3 for the bottom, and M2 for the top. Simply solder each wire to their nut. You can use as many as fake cells short circuited as you need. You can supply, for example, 6v to the first battery and using 3 bypassed cells. Also you can just supply the first and the last cell, with their polarity. Enjoy.