Keys are commonly produced in two kinds of materials, iron and brass. Obviously, brass keys will be a better choice to avoid rust.
Key thickness partly determines the strength of keys, most of keys in the door lock market are 2.0mm thick or 2.2mm thick, only a few keys are 2.5mm thick which definitely helps low down the possibility of being broken.
There are several high-technology keyways including angle-cut-pin keyway, computer keyway, double-row-pin keyway, and dual keyway (one-side single-row pin, one-side track-cut pin), etc. These keyways have higher security especially the dual keyway, which is global first-creative revolutionary design to combine track and pin technology.