The size indicated on the box is; M/L. I agree with hjwagner, the strap is indeed very comfortable.

Mine was M/L. I have a relatively large hand and it fits perfectly, I have no problem taking it off, which is important for a watch with such a short battery life.
The strap is very comfortable to wear.

In the specifications (click on show more) it says that it is an M/L bracelet.