Via ferrata is climbing long distances on almost vertical rock faces in beautiful sceneries. A climber need a via ferrata belay device, a normal rope climbing harness, a helmet, climbing gloves, and hiking shoes. On the route, there is a steel cable or some other protection. There might also be ladders, bridges, etc. The easiest routes are pieces-of-cake even for beginners in average condition.
If the route is long, also take a backpack where you can pack snacks and something to drink, especially if it is sunny. Many people think that when it is warm, you should have approach shoes instead of hiking shoes. The best choice for gloves is strong fingerless gloves particularly designed for via ferrata. Even though they are not obligatory, they protect your hands from the steel cable.
Information on Via Ferrata [Wikipedia]