Check the listing for details. 20pcs M3 304 Stainless Steel Rivet Nuts Flat Head Insert. Condition: New, Made in China. Listed at 11.22 USD. A Rivet Nut fastener is a tubular rivet with internal threads.It requires a tool or device to install in seconds form one side of the work. Once installed, no finishing work is required.The added benefit of not only being a fastener, they are ready to use with clean threads available for screw attachments.The material is too thin to machine the thread.Blind 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 work piece. Specification:Product Name: Rivet NutMaterial: 304 Stainless SteelGrip Range: 0.5mm-1.5mmThread Size: M3x0.5mmDrill Hole Size (+/-0.1): 5mm / 0.2"Total Size: 9x7mm / 0.35"x0.28" (L*Max.D)Package Content: 20 x Rivet Nuts.