In a search for keys, Duet's map pointed to a spot off the west coast of Africa Interesting… In a search for keys, Duet's map pointed to a spot off the west coast of Africaon.wsj.comThanks to new Bluetooth tags, your keys, wallet and purse should never go missing again. Joanna Stern tests three tracking devices…

In a search for keys, Duet's map pointed to a spot off the west coast of Africa Interesting… In a search for keys, Duet's map pointed to a spot off the west coast of Africaon.wsj.comThanks to new Bluetooth tags, your keys, wallet and purse should never go missing again. Joanna Stern tests three tracking devices…