Sternglas Watch Marus Automatic Black Steel S02-MA03-ME03. For a long time STERNGLAS watches have been asked for a swimming and diving watch. Several prototypes later Sternglas can now present their first timepiece in this distinctive style. In order to achieve a particular high water resistance the case back and the crown are screwed. The watch case is manufactured using high quality steel and equipped with Sapphire Glass. As a visual highlight you find on the reverse an engraving of an abstracted seabed.