What is a 710?

A blonde walked into her local garage and asked for a seven-hundred-ten

The mechanics looked at each other with a puzzled expression, and another customer asked, 'What is a seven-hundred- ten?'

She replied, 'You know, the little piece in the middle of the engine, I've lost it and need a new one,' continuing that she didn't know exactly what it was, but that this piece had always been there.

The mechanic gave her a piece of paper and a pen and asked her to draw what the piece looked like. She drew a circle and in the middle of it wrote 710. He then took her over to a car just like hers which had its hood up and asked 'is there a 710 on this car?'

She pointed and said, 'Of course, its right there.'

If you're not sure what a 710 is have another look at the picture above!