20Pcs M4 M5 M6 Rivet Nuts Thread Half Hexagonal Carbon Steel Flat Head Threaded Nut Insert Rivnut Nutsert for Screw Attachments Feature: A Rivet Nut fastener is a tubular rivet with internal threads. The material is too thin to machine the thread. It requires a tool or device to install in seconds from one side of the work. The added benefit of not only being a dependable fastener, but they are also ready to use with clean threads available for screw attachments. Rivet Nuts also are used when an application has little or no access to the backside as they can be installed from the front side of the workpiece. Specification: Material: Carbon Steel Finish: Black Zinc-Plated Thread Size: M4x0.7mm / M5x0.8mm / M6x1mm Drill Hole Size (+/-0.1): 6mm/ 7mm / 9mm Total Size(L*Max.D): 11mmx9mm/ 13mmx10mm / 15mmx12.5mm Package Content: 20xRivet Nuts _x000D_