Our cage nuts range from M4 to M10, 1/4-20 to 10#-24. These cage nuts are designed to fit a 3/8 inch square hole for punched panel rails, often found in industrial applications. They are made of hardened 0.35-0.5mm spring steel for heavy and light application. They are available in Zinc, Yellow Zinc and Black Oxidation finishes. Some sizes are also available in stainless steel.