Don't get the smallest size. I had a standard small one in my truck a few years ago...was headed up to Ohio and saw a panel truck on the interstate in W. VA with flames coming out of the engine compartment. My bud and I stopped and I almost got the fire out but not quite. It took off again. We spent the next 5 minutes at the butt end of the truck hauling out everything we could while his 8 yr old daughter stood on the side and wailed and screamed...everything they owned was in that truck. He was a young black dude in dredlocks, nice fellow, a dental technician (made dentures). What got my attention was the tanks of gas (oxygen and acetylene) in the back. We managed to wrestle them out and away from the van and just threw all we could onto the shoulder. Finally the flames ran us out and we watched it melt (aluminum body). The State Patrol showed up then with a large fire ext...we could probably have saved it all if I had had a bigger one.I saw a car catch fire in the mcdonalds drive through way back when. I gotta get a fire extinguisher for the truck, havent had one in there for a while.