From their website:
Fantasy Flight Games is pleased to announce an exciting new product now available for the Descent: Sea of Blood expansion. For players looking to enhance their voyages in the waters of Torue Albes, your ship has come in.
Now you can master the waves in style with the Sea of Blood Ocean Map Board. With a beautifully rendered island on one side and open ocean on the other, this double-sided, folding tactical map board replaces the Ocean Poster Map from the Descent: Sea of Blood expansion. Its sturdy cardboard lays perfectly flat when you’re playing and stores away easily when you’re done. Head to your friendly local retailer and pick up your copy today, or head to our webstore.