Knurled cup head, convenient for hand screwing, simple installation and not easy to slip.Wear resistant spiral thread, uniform stress, solid thread, smooth rotation and not easy to slip.The groove depth and specification are standard dimensions, the surface is round, the stainless steel material is selected, and it is corrosion-resistant in humid environment.The diameter is 1.4mm-20mm and the length is 3mm-150mm. Various specifications and sizes are available.