Load test shall be carried out for new hook, and the measured opening of hook mouth shall not exceed 0.25% of the original opening. During use, the hooks shall be frequently checked for cracks, serious deformation, corrosion and wear. The hook shall be tested once a year. During the test, the static test shall be carried out with 1.25 times of the allowable working load for 10min. The magnifier or other methods shall be used to check that there shall be no cracks, cracks and residual deformation.