The Time Harvester was a device supplied by Mr Symington and Mr Blenkinsop as help for business people. Both co-workers, Andrew Brown and Sameera Jenkins were competing against each other for a promotion, using these Time Harvesters as an advantage to impress important people.
Amy was persuaded by Sameera to have one. She found it so addictive, that she crossed over her timeline many times, to help Rory and then the Eleventh Doctor and also meet her parents within twenty-four hours. The Doctor was displeased. He tried to remove it from her arm, but it was held sealed. Amy soon discovered that the interest on the Time Harvesters was much more than she believed.