MIAMI – Burger King will offer Whopper sandwiches for a penny if customers use its new BK app within 600 feet of certain McDonald’s restaurants.

The company is calling the new promotion the “Whopper Detour.”

The limited-time offer works by geofencing McDonald’s locations around the US where Burger King customers can unlock the promotion price for the Whopper. Burger King then wants people to place their order and pick it up at the nearest Burger King location.

According to the Burger King release, there are about 14,000 locations where customers can redeem the offer.

Customers are eligible to take advantage of the offer once, between Dec. 4 and Dec. 12 at participating Burger King restaurants nationwide.