Oh my goodness! It turns out it was a bonus and I didn't even know enough to realize it! I ordered VK-1000 and VK-2000 kits.
Thanks for the bonus!
I assume the one currently on the website is the version that will power a passthrough in the car? I will keep it in mind for future orders.
Since I have your attention, do auto batteries and pass throughs need cleaning occasionally? (They draw much harder than they did at first, even with a new cart.) If yes, is there a video on how to do it?