Not much! I keep a folding military shovel, a set of jumper cables, some general handtools in a soft bag, spare tire and jack of course and spare fuses and bulbs. Since it is so hot here, I do not store water, food or anything that will melt, like duct tape! I keep a quart of oil, trans fluid also. When I am going out in the wilderness with it, I carry a 5 gal container of water, not especially for drinking and a tow strap. I have 4wheel drive and don't exactly go in really rough terrain, just bad roads occasionally. I always have my cell phone with me and if I am going away from cell coverage I carry an external antennae with my HAM amatuer radio and a repeater guidebook. In town I always have the cell and usually a quart of water if on the freeways, sometimes hard to get off of if having a problem in heavy traffic. If I was adding one more thing it would be what we call a come-a-long. It is a hand operated winch type thing, lever and ratchet with a cable to help winch the vehicle out of a bad spot. Anytime I am off in the wild areas I have general camping or backpacking gear, so that covers most non-vehicle emergencies.