The 710 cover

 

 
 

A blonde walked into an auto accessory parts store and asked to purchase a "710 cover" for her car. The clerk replied that he had never heard of a such a part. . She explained that her car had always had one since new, but she noticed it was gone after the last servicing.

After spending an hour checking parts catalogues and consulting with other staff members, one of the service agents asked her to describe a 710 cover. She held up her hands and made a circle about 2 inches. He still didn't understand, so patiently asked her to draw one.  (By now, of course, several employees watching the proceedings.)

The woman drew a circle (with an edge like a flower) and wrote 710 inside the circle.   The employees standing at the opposite side of the table started to laugh, then everyone joing in.  Here's the 710 cover she drew.