Beretta PX4 (Storm)
9x19mm or .40 S&W or .45 ACP
Released in 2004 this polymer and steel-insert pistol incorporates a variety of newer features such as changeable 3-dot sights, smoothly curved trigger guard for concealed carrying and a system of simple and quick field stripping.
This pistol offers one of the most custom systems with the many parts being interchangeable. These include the grip backstraps (three sizes: slim, standard and oversized), magazine release button (either side plus sized as standard, large or combat/extended), slide lock catch and the hammer mechanism.
It is in use in a variety of police forces in the US and other countries.