The other day I was in Halfords. A lady comes in and asked for a seven ten cap.  We all looked at each other and said, "What's a seven ten cap?"

She said "You know, it's right on the engine. Mine got lost some how and I need a new one."

"What  does it do?

She said she didn't know, but its always been there.

The assistant gave her a note pad and asked her if she could draw a picture.
So she makes a circle about 3 inches in diameter and in the centre she writes 710.

Here's what she drew...  

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