Samsung has started selling the Band Adapter for the Gear S2, which was leaked last month, in Germany. Priced at €27.5, the adapter allows a Gear S2 user to pair any standard watch strap with their smartwatch, which is not possible otherwise. It is currently on sale through telefon.de in Germany, and might become available in other European and North American markets soon.
Unlike the Gear S2 classic, the Gear S2 comes with a proprietary adapter that is compatible only with watch bands released by Samsung. If you want to pair any other watch strap that caught your eye at a usual watch store, you'll have to use this band adapter with the non-classic variant of the Gear S2. It is available in dark gray and white, so you can choose the one that suits your smartwatch.