resistor box? what?

I just want to know what is the resistor box
I know that it's required to convert the dual point injector to multi.
But how does it hook up?
If i'm using everything from an LS (intake manifold, Ecu, etc...), will I still need this "resistor box"?
Please help if you know

the injectors on our cars are peak and hold style, which require a resistor box to operate correctly. I havent really looked at mine, but you run the injector wires through that, then they go to the harness. The 92 and up civics have saturated injectors, which dont require a resistor box. I assume youre swapping an ls in your car? the only way you wont need the resistor box is if youre converting your car to be obd1, and thats a day at the park itself.