A blonde walks into the auto parts store and asks the countermen for a seven ten cap. They ask what a seven ten cap is? She replies that she doesn't know, but its a cap that was always on the engine, but now its gone. So she needs a replacement. They said they have never heard of one but if she would describe it, they would try to find one. So the blonde says its about 3 1/2 inches in diameter and has the numbers 710 written on it. The guys ask her to draw it out. She starts drawing the circle and adds the numbers 710. The guys, as they see the drawing come to life upside down in front of them, say "You mean OIL not 710" "Oil Cap, 710 cap, I don't care just get me one and what's so damn funny anyway."