The TAPPI T 543 standard specifies a method for measuring paper and Cardboard flexural strength using a Gurley tester. This method evaluates the flexural performance of paper by measuring the force required to bend the specimen under controlled conditions. During the test, the specimen is clamped in the tester, applied force to bend it to a certain angle, and the instrument records the required force value. Flexural strength is a key indicator of paper stiffness and flexibility, and is widely used in paper quality control, product development, and printability evaluation. This standard provides the paper industry with a standardized test method to help optimize paper performance and ensure its Reliability in practical applications.