I'd say Isaia runs about 1 size smaller than most suits you'll find on the RTW market in America, including other Italian makers. If you can fit a 41R in an Oxxford or Brioni even, in a lot of Isaia models you could take the 52R. But it depends on the model. If you wonder about sizing, remember that using the riddle (the answer is "skateboard" -- you may have to post the question and where you found it as well, so do a Google search) will get you free shipping as well. No clue when this expires. Good on everything.