[Cooker]

I think this raise is pretty standard, but I don't think it is much of a semibluff. I wouldn't be surprised if villain has only some kind of draw (probably low only, but he might have A34 although I would bring the pain with that holding if I were him) and is making blocking bets, although I have seen some weak players tread carefully with lower sets this way as well. Still, I think you are often against A3 with nothing else, so you are probably raising for value here.