I'm an auto mechanic and I work with battery cables all the time, these cables are really 4 gauge, don't let the insulation fool you, the insulation is really thick like audio equipment cables But overall the cable is very flexible , and it seems like a great deal at over $40. I use them to easily transfer 50-100 amps from my alternator to my battery pack. I haven't checked the voltage drop on the wires, but they don't even get hot.