That particular model, Beretta Elite II, shoots only .177 BBs. It is made by Umarex, one of the best CO2 action pistol makers. I don't think this is one of their better guns however, it is all plastic and doesn't have a good feel to it. If you are looking for a good, fun and realistic air pistol I would recommend the HK P30, Beretta PX4 Storm or Beretta 92F. These are all made by Umarex and are all very good guns. The P30 and PX4 are both capable of firing either BBs or pellets but I would highly recommend only using pellets because the steel BBs will damage the barrel rifling. Go to Umarex's website and check all the models they have available. .umarexusa.com
I would highly recommend the HK P30, it is a fabulous pistol and is identical in weight, size, and feel to its live fire counterpart. I have put thousands of pellets down the barrel of mine and still can't get enough of it..