Chokes confuse most people, us included!  Our advise if you are shooting game is stick with Quarter & Half and forget about them.  If you are shooting clays and want to start experimenting the below table might help.

Choke Table.png

For further reading The Field's guide is very useful.  

If you need help identifying which type of chokes your Beretta uses, the guide on their website has everything you need to know.