They plug right into most popular models of 6S lipo balancing chargers that have 7-pin balance ports with 2.5mm pin spacing.
Battery packs must be of the same cell count (only charge 2S with 2S 3S with 3S etc.) and battery voltages must be within 0.1V per cell (0.1V for 1S 0.2V for 2S etc.) of all other batteries connected to the Paraboard at the same time. Use a Cell Spy or similar voltage tester to check the voltage of each cell before connecting to the Paraboard.