Steel or stainless steel 1.4310.

Steel electro zinc-plated.
Stainless steel bright.

Split pins are used in machine construction and automotive engineering as retaining elements. They are often used for securing castle nuts. After the split pin is pushed through a hole, the ends are bent over to ensure a secure lock.

The split pin can be shortened. As a rule, the split pin should be roughly double the length of the hole.

As the material structure can weaken through bending and straightening, the split pins should not be reused after they have been removed from the hole.