There are different sizes, M3, M4, M5, M6, M8 and they normally have a low profile compared to other nuts With an open end, a small flange, a round hole, a threaded inner wall and a non-slip surface partial, these flat head rivet nuts have good performance of fastening function Comes with a rivet gun and many mandrels and noses for convenient riveting The rivet nuts are made from a aluminum alloy that provides strength, corrosion protection and long life Each size includes many pieces of rivet nuts so you don't have to go to a hardware store to search for rivet nuts for a while Features: Spezifikations: Material of the rivet nut: aluminum alloy Type: flat head rivet nut Nut thread: M3, M4, M5, M6, M8 Rivet gun size s: 9.7*27cm/3.82*10.63in Package includes: 20pcs x M3 Rivet Nuts 20pcs x Rivet Nuts 20pcs x M5 Rivet Nuts 10pcs x M6 Rivet Nuts 10pcs x M8 Rivet Nuts 5pcs x Chucks and Nosepieces (M3, M4, M5, M6, M8) 1pc x Rivet Gun