Evidence of time travel in Chinese tomb ?

In December 2008, Chinese archaeologists allegedly removed the opening of a 

giant coffin within what was believed to be an undisturbed, 400-year old Si Qing 

tomb in Shangsi County.

As they removed the soil around the coffin, however, they were shocked and 

amazed to find this:

A small piece of metal shaped like a watch, with the time frozen at 10:06.

“Swiss” was engraved on the back.

If the tomb was truly undisturbed for 400 years, what could explain the existence 

of this modern artifact?