That looks like a 2.7 ohm 5W power resistor. You should be able to check it with a volt meter set on ohms. You should probably read 2.7 or possibly less if they are in parallel. I normally order electronics from digikey.com, but I don't normally work with anything that big mostly surface mount components. If they are burned up you should have a very high resistance just like the ballast resistor on your duster.