Extra-tough, three-ring binder is built to stand up to the most abusive use conditions. It is almost indestructible with round rings for easily storing up to 450 letter-size sheets. Durable vinyl covers feature heavyweight inner chipboard core. Label holder on spine simplifies identification of binder contents. Case-bound binder also features metal hinges and 8-1/2 centers and 3-1/2 ring-to-ring dimensions.