1. Sturdy and durable: made of high quality stainless steel. 2. The knurled nut makes it easy to insert into the workpiece. 3. Can be easily installed in many different materials including steel, plastic and fiberglass. 4.Type: M3 M4 M5 M6 M8 M10; Packing quantity: 165pcs; Comes in a convenient plastic box. 5. Excellent rivet nut installation tools, making the job easier and faster.