The magnetic compass was a compass that had a magnetized needle supporting a magnetic card. This compass showed from four to eight directions. This innovation helped the Age of Exploration flourish because it showed explorers what direction they were headed. So basically it helped explorers reach their destination.
I think the answer you're looking for is a compass, more specifically a magnetic compass, which is a compass that had a magnetized needle that pointed to the magnetic north pole, always showing them which way was north, giving them a sense of direction. Hope this helped.
