The incident took place in the court when the guard present in the courtroom spotted it and asked the person wearing it about the device.
When the matter was reported to Special CBI Judge O P Saini, he wondered how was it a watch as it was not showing time and had no dial or display.
"This does not appear to be a watch," the judge asked.
One of the lawyers inspected it and said he could not say whether it was a watch or any other device.
Pankaj Pandey, STPL's authorised representative who was wearing the instrument, told the court it was a "fancy watch" which he had bought online.
On being asked as to why the watch was not displaying any time, he said it had stopped working.
Senior public prosecutor K K Goel told the judge that if the court passed an order, CBI would get the watch examined through a forensic test.
The court, however, warned Pandey to be careful in future in the courtroom and not to bring such devices.
The court was hearing final arguments in the case in which former Telecom Minister A Raja, DMK MP Kanimozhi and 15 others, including some top corporate executives, are facing trial.
