It is widely used in frame combination of light truncated structures with low stress, strength and support requirements, as well as in special fields such as automobile, factory automation, industrial module structure, etc. It is one of the most widely used profiles in industrial frame. Matching bolt nuts: It usually uses 20 series M5 (majority) or M4 special T-type nuts to connect with the inner hexagon. If the strength is high, 20 series slider nuts can be used to connect with the inner hexagon bolt, which is strong kekao.