- Sturdy and durable: Made of high quality stainless steel. 2.Knurled nut makes it easy to insert into workpiece. 3. Can be easily installed in many different kinds of material including steel, plastic and fiberglass. 4.Type: M3 M4 M5 M6 M8 M10; Package Quantity: 165pcs; Comes with a handy plastic box. 5. Great rivet nut installation tools to make the job easier and faster.