Changed belts on the Miata, the alternator belt was really bad, it's behind the power-steering/water pump belt, so changed them both. They're 4-ribbed flat belts, like two tiny serpentine belts.
Bought Continental belts at Quinte Truck and Trailer, significantly cheaper than the NAPA stuff around the corner, both businesses are owned by the same company.
BTW, Continental owns the Goodyears Gatorback name and has phased it out, the same belts are now Continental branded.