M3*40 Dimensions: Thread diameter: 3mm, Tooth length: 15mm, Total length: 40mm, Outer diameter of the ring: 19mm (Product dimensions in millimeters, 1mm = 0.0393701 inches) 304 stainless steel, high hardness, resistance to corrosion, can be used in humid environments and do not worry about rust Product advantages: Screw bolt has eye made of 304 stainless steel external thread, self-tapping screws, consisting of: very large machines. After many experiments, it was accepted. proved that the outside will not be oxidized. and rusty. Can be used in humid and humid environments. outdoors The balls outdoors sheep's eye, also called sheep's eye, sheep's eye rings, nails sheep's eye, screw on; œEye of sheep, etc. . It is also one of the most common hardware accessories for architectural decoration.