The GB/T 2423.4-2008 standard defines the test method for electrical and electronic products under alternating heat and humidity conditions. The test simulates the long-term use of the product in a heat and humidity environment, including a cycle of 12 hours of heat and humidity and 12 hours of drying. The standard details the test equipment, operating procedures and evaluation criteria to verify the Reliability and Stability of the product in a high humidity, high temperature alternating environment.