1.Thin type knurled thumb nuts. This is a carbon steel knurled nut. 2.The circular nut with knurled is easy to assemble and disassemble.3.Made of good quality carbon steel material, nickel plated finished, wear-resisting and durable to use. Specification:Material: Carbon SteelFinish: Nickel PlatedThread Size: M3 x 0.5mmOutter Diameter: 11mm / 0.43"Height: 3mm / 0.12"Package Content: 30 x Knurled Nuts