Limited Edition of 1883 Pieces. Alpina Watch Seastrong Dive Gyre Blue Mens Limited Edition AL-525LNB4VG6BLK. Alpina watches is harnessing the power of these gyres in a new and actively engaged range within the Seastrong collection. Its name, Seastrong Diver Gyre Automatic. For the first time in the history of the Maison, the Seastrong Diver Gyre Automatic range features a case comprised of 70 percent plastic debris derived from fishing nets collected in the Indian Ocean. To ensure its durability, it has been strengthened with 30 percent fibreglass.