Introduced in 1988, the Sea-Dweller 16600 is the heavy-duty brother of the Submariner 16610 of the same era. Compared to the Submariner, its case -now fitted with a helium escape valve- is slightly thicker. The glass does not feature the cyclops. The 16600 was replaced by the Deepsea 116660 in 2008.The pictured watch was made for the COMEX diving corp. There were two batches of 16600 delivered to Comex; one in 1992 with straight COMEX engraving on the caseback and another batch with rounded engravings in 1997 such as the present watch.