This standard specifies the product classification, technical requirements, test methods, inspection rules and markings, packaging, transportation and storage of cardboard stiffness testers. This standard is applicable to Taber type cardboard stiffness tester and letter stiffness tester (hereinafter referred to as "stiffness tester") designed based on the principle of Taber type stiffness tester. The periodic technical status inspection of the stiffness tester during use should also be used with reference.