... . 3.function:anti-loose, buffering Item NamePan head electronic combination screw fastenerMaterialCarbon steel, stainless steelSurface treatmentZinc, colour ... ect..And it can be made environmentally friendly.SizeNon-standard, so you can chose it.StandardDIN, ISO,DIN, ... square washerFunctionAnti-loose and buffering1.Product Profile Pan head electronic combination screw fastener is an accurate screw. It ...