Iron padlock is very common to use. there are many types, which can belong to this category；
A. Electroplated iron padlock: table
B. Gray iron padlock: The surface is treated with gray paint, after which many colorful padlocks appear, all of which belong to this category.
C. Imitation copper padlock: In fact, it is an electroplated iron padlock, which means the surface is plated with copper