I've had a few of these 'flag' style rally isolators and most have fallen apart. Inside they have been a tin washer barely capable of carrying the power from an AA battery. But today, after replacing my rear winch isolator with one of those bad boys, I took this one apart for a look. Rather surprisingly, it's pretty good. Now I don't think it's really right for the currents needed in winching, but it's not bad. Pretty well constructed and the copper is quite thick. I didn't measure it, but it has to be around 30mm 2 or thereabouts. So enough for a normal battery isolator set up.
