1、Made from zinc plated carbon steel which provides strength, corrosion protection and long service life. 2、With open end, small flange, round hole, threaded inner wall and partial anti-skid surface, this flat head rivet nut has a good performance as fastener. 3、Convenient to install, designed to form a bulge on the back side of the panel as a screw is tightened in its threads. 4、There are four different sizes from M3 to M6 that you can choose as needed for various purposes. 5、Each set includes many pieces of rivet nuts so you don't have to go to hardware store searching rivet nuts for a while. Features: Made from zinc plated carbon steel which provides strength, corrosion protection and long service life. With open end, small flange, round hole, threaded inner wall and partial anti-skid surface, this flat head rivet nut has a good performance as fastener. Convenient to install, designed to form a bulge on the back side of the panel as a screw is tightened in its threads. There are four different sizes from M3 to M6 that you can choose as needed for various purposes. Each set includes many pieces of rivet nuts so you don't have to go to hardware store searching rivet nuts for a while. Specification: Material: Carbon steel Surface Finishing: Zinc plating Color: As pictures show Type: Flat head rivet nuts Size and Quantity: M3  50pcs M4  50pcs M5  50pcs M6  50pcs Package list: 1 * Set of Rivet Nuts (200Pcs)