Test Properties: comprehensive performance test, Assessment of seat covers in the vertical load capacity of endurance. Specimen: the whole chair, all kinds of chair. Test program: Composed with impact test and Static front test Impact test: Impact the chair with 125 pounds standard sand bags at 10-30cpm speed 100000 times. Hydrostatic test: press the chair around the corner before and after slowly with 10-30cpm speed 20000 times. Results evaluation: The whole chair will not lose the function after testing.