It happened on Sept. 30, authorities said.
The suspect walked into the Breitling store around 7:30 p.m. and asked to see a golden Super Chronomat B01 44, according to police.
He was last seen running toward the Nordstrom's store.
The suspect is described as a bearded man with a thin build between 20 and 30. He was wearing a black hat, a black jacket, a white T-shirt, and black joggers.
Anyone who can identify him is asked to call the Upper Merion Police Department at 610-265-3232 or submit an anonymous tip online.
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