The vast majority of those Li-Ion jump packs are severely overrated, and "IF" they can even deliver 100A or more (at a cranking voltage, current at short circuit is meaningless), need a cutout circuit to keep from damaging themselves after a few seconds cranking.
Thus the best way to use them is on a drained, not electro-chemically compromised, dead battery, where you put the jump pack on and let it get some charge back into the primary battery, waiting as long as your patience allows (minutes or more).
This can work through a lighter outlet if it isn't terribly corroded, and of course is electrically connected in your off or aux vehicle ignition switch state (keeping fans, lights, radio off etc), but obviously not as well as having a higher amp capable direct connection to the battery through clamps.
So 4 x 18650 cells in it, or equivalent flat packs. No real need for direct connection to the battery for something that low capacity, it's going to be one of those "one shot" types where the only hope for all but the smallest engines in warm weather, is getting charge back into the primary battery, or of course if it wasn't very drained in the first place.
It's easy to market the Li-Ion for small size and low cost but then you get low performance. It costs roughly 3X as much to get some true capacity from one as just using a SLA battery instead, but can still be handy to recharge a phone, keep vehicle memory when swapping the primary battery, or long lasting flashlight for emergencies if it has one built in.
