The Beretta 90-Two is an Italian semi-automatic pistol. It is an enhanced version of the Beretta 92.
The Type F is a double/single-action (DA/SA) pistol with a manual safety that also serves as a hammer decocking lever. The Type F operated the same way as the Beretta 92F.
The Type G is a double/single-action (DA/SA) pistol similar to the Type F, but there is no manual safety feature, the 'safety' lever serves as a hammer decocker, similar to SIG pistols.
The Type D is a double-action only (DAO) pistol. The hammer follows the slide to the uncocked position with every shot, required a double-action trigger pull for each fire. There is no manual safety, half-cock hammer notch, or hammer drop lever.