They are produced from high quality brass alloy and exceed the specifications of the German standards. The raw material has gone through a special heat treatment to achieve the desired hardness. In the product, during its processing, internal stresses develop resulting in an increase in hardness. The final product is now subject to heat treatment for a second time in order to remove the stresses created by its processing and to zero out the chances of cracking (season cracking) as well as to restore the desired hardness.