OneTigris Metal Gym Rings Heavy-duy Gymnastic Rings w/ Adjustable Straps Not very heavy-duty? Not Durable? Not Strong? Check OneTigris Metal Gym Rings,made of Solid Steel A 7 diameter round ring made from polished steel for a beautiful lasting shine The inside diameter is approx 6 2/3 inch The strap must inserted through the bottom opening of the buckle & it will not slip Unlimited body-weight exercises that engage your muscles and core