I carry a full set of tools----SAE and METRIC-------sockets open and box wrenches hammers, screwdrivers, pliers,multi-meter, Torque wrenches and a bunch of other stuff to mechanic with. Saws, drills, etc. I have all the welding products needed except for a welder. I use jumper cables and 3 ea. 12 volt batteries to weld with.
since 1986 and full timing most of that time I had everything I needed except one time my utility trailer tongue cracked and I had to find a Welder. Too big a job for me and my Battery welder.
Someone mentioned Tape. Make sure you carry DUCT tape and not Duck tape. Big difference.
Marvin