Thieves snatched a special speedometer from a driving instructor's car.
They broke into Robert Floyd's Nissan Micra and ripped out the important piece of equipment.
The car was parked in his drive in Hampstead Avenue, Clacton, when the raiders struck overnight on Sunday.
The 39-year-old has appealed for car dealers and members of the public to look out for the £200 item.
Mr Floyd, of Learn To Pass, said the secondary speed clock is only of any use to driving instructors.
"I use it to keep an eye on the speed if I can't see the speedometer on the dashboard clearly," he said.
- Anyone with information about the break-in or who has seen the item should call Clacton police on 01255 221312 or Crimestoppers on 0800 555 111.
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