The 5165 is a transitional reference that not many people know about. It was introduced in 2007, ten years after the introduction of the first Aquanaut. 

It has the updated calibre 324 SC like the 5167 but it still has the original 'Jumbo' case diameter, which is 38 mm. This is slightly smaller than the 5167 and in our opinion this is a much better, more wearable size. It has a stainless steel, highly-polished case and a brushed finish on the round, octagonal bezel with polished bevelled edges. It has the typical black, textured dial that matches the tropic (rubber) strap. It has an 18k white-gold applied Arabic index with luminescent material and the date on the 3-hour position. Of course this watch comes with a tropic (rubber) strap with butterfly clasp.

While the 5165 was only in production for a couple of years this one dates back to 2010. This is probably because this reference was not that popular and languished in dealer displays for years after its production had stopped. Because of this the 5165 is pretty rare and collectible nowadays. Initially sold by Gubelin in Luzern.