The problem with ordering one by the internet is you don't know if it has the correct BRUSH(s) type blower fan in it or not. This is what I use now.
It is 12vdc / 12.5 Amps / 180 watts (600 BTU).
Like i said before it works great for those mega hurricane like winter days and all thunderstorms. So as long as your Ametek don't go over 200watts. I'm not sure how to read the Ohms, but here is what it says on the 2 ohm scale of my meter. It has to be very low ohms to STALL my DC generator as it does. It is probably less than 1/4th of a ohm. Amazingly, this is made in the USA!!
I have another one (new,never opened) exactly like the one I use if you want it. You can have it for what I paid, half off was $15 and about $5 for shipping. (I have daily UPS pickup for my business) Just email me if you want it. I don't think I will need it, I am making my own multi-element, multi-switching heater. (electronic controlled according to load on mill)
Here are the insides:
It has a simple straight heating element and blower. Of course, the heating element is the same as a big resistor I believe. You can see the little brushes thru the hole there. If you buy one from the store, take it apart and make sure it has BRUSHES and NOT the type that is a Brushless blower fan with transistor. The voltage drop goes down to around 7 volts when hooked up to your genny in a big wind , so this always blows out the little transistor in the little blower motor. So like the photo I had previously posted with the extra blower fan taped on top (I don't use it no more actually).,, that one is a pain in the neck, because that fan is also a brushless type and i had to hook it to my 12v battery bank SEPERATEly and let it run all night even if there is no thunderstorm.
The far better way is the BRUSH type blower which turns on only when it has to...when the heating element turns on during a very strong wind gust.(40mph+) It is completely self-contained and wastes no power. I should have never showed the first picture with the taped on fan. I hope I'm not confusing anyone. As for the polarity question, I don't know,,,I identified the positive wire from the center of the cigarette socket thing and put tape on the wire to keep polarity the same. It would probably work both ways on the BRUSH type blower fan, but NOT on the transistor type BRUSHLESS blower. And yes, you simply cut off the cigarette socket. -Hope this helps.