Missing Part

A blonde woman walks into an auto parts store. The associate asks how she is doing and what he could do for her.
She replies, “I’m fine. I need a seven-ten cap for my car.”
The man asks,” A seven-ten cap? Where does it go, I’ve never heard of such a thing?”
The blonde angrily replies, “It goes on top of the engine and don’t think just because I’m a blonde woman I don’t know what I’m talking about!!”
Perplexed, the parts man asks if she would draw him a picture that might help him figure out what it is she needs.
The blonde takes the paper, draws a shape of a cup and in the middle writes: 710.
As the associate sees it from across the counter, he smirks and hands her a new oil cup. With a note of sarcasm he says, “You’re right, being a woman has nothing to do with this.”