If one needs a single tool, Vise-grips are it. On a motorcycle I have used one as clutch or shift lever or attached to a broken throttle cable. You can turn a screw if you can reach the side of it with this tool . Lock one down to something under the hood; you might not like to bugger up a bolt, but you won’t care if you are no where near tools. If required, you can rip sheet metal with one. Wire cutting too. You can clamp it down hard enough to hit it with a hammer. Vise-grips and a crowbar are thieves’ favorite tools. Buy the small size; and only the brand name: these are made of high-strength steel.
– C. Bridger
And they come in a whole tribe of specialty varieties. The standard should be in everyone’s tool box, the small one in every emergency pouch, and you should at least know about the others. The same relentless leveraged but sensitive clamping action works with super wide vise-grips, narrow ones, wide necked ones, nut cutters, curved necks and so on. They are extremely handy.