It can be left hand or right hand draw.
The magazine sizes are listed, but the standard is a double stack 9mm/.40S&W magazine (Glock 19/17) or a double stack .45ACP/10mm magazine (Glock 20/21).
That really depends on what Beretta handgun and the size of the magazines. If it is a double stack magazine for something like a Beretta 92, then the "Glock 17" model would most likely work.