Wootalyzer’s Pricing Post! - The price of today’s woot item is saved here for future reference
29-Piece Road Side Emergency Tool Kit with 10 Gauge Booster Cables - 2 Pack
$14.99 + $5 Shipping
Condition: New
DISCLAIMER Wootalyzer! is in no way affiliated with Woot!, and this post may not always be here!
Try jump-starting your car through those puny 10-gauge cables, and the cables will probably melt. 10-gauge wire is rated at 30 amps maximum, most automotive starter motors draw over one hundred amps.
I got one of these in my last Bag’o’Crap. But there’s so much more to it! I woke up in a bad mood, and my fiancee suggested that I go out and test drive some cars to get myself feeling better. Well, I ended up driving one of the cars home to pick up the paperwork I’d need to actually purchase the thing, and BAM! right when I walked out the door to get head back to the dealership the mailman hands me my BOC, with this little bad boy inside. It was the first thing I put in the trunk of my new baby 
Buy one, and you might get a new car too!
That figure is for household wiring, given typical cable construction (usually 10/3 Romex), runs through conduit, and continuous current flow.
The current rating for a 10-gauge jumper cable being used solely to jump-start a car is considerably higher, probably in the range of 150-250 amps, though ultimately the figure is somewhat subjective; different testers can make different but reasonable assumptions regarding the duration of a jump start, the acceptable temperature rise, and so on.
The real reason to prefer heavier gauge jumper cables is that the heavier cable will have a lower voltage drop, making the jump start faster and more reliable.
Personally, I carry a 15-foot 2-gauge cable with forklift-type quick disconnects (Anderson PowerPole connectors), two sets of battery clamps with quick-disconnect connectors, and one more quick-disconnect connector permanently attached to my battery. I figure if I can’t solve a problem with that stuff, it probably can’t be solved that way.