Square Rivet Nut by Cold Forging.Size: M4-M8, Plating:Yellow Zinc Plating, White Zinc Plating and Black Zinc Plating Type: flat head/ thin head/countersunk head circular body/knurled body/full-hex body/half-hex body/open-end/ closed-endSize: Metric thread: M3~M12 Inch Thread: UNC6-32~1/2-13Material: steel, aluminium, stainless steel, brass Square Rivet Nut