The Seiko Kinetic Scubamaster is not the most expensive watch I own, but it is probably the rarest and most unique. In fact, I think it comes pretty close to being the ultimate diver watch. It is feature rich, extremely tough, very accurate, and has a bold, distinguished look. Here’s a feature-by-feature breakdown:

The watches I cover in this article go way deeper than your typical diver; deeper than the current 1,220 meter Rolex Sea Dweller; deeper, even, than the Breitling Steelfish which maxes out at a comparably casual 2,000 meters. There are a handful of watches out there that can literally scrape the bottom of the deepest known parts of the ocean, and I call these watches “extreme divers”.

I find the overall presentation of the head of the MTM Black Seal to be exceptional. The red of the chapter ring between the 12 and 3 o’clock positions, the highly visible orange hands, the polished and reflective indices, and the yellow MTM seal against the black sheen of the carbon fibre dial all come together to give the MTM Black Seal a striking appearance. An added benefit of the silicon filled case is that it makes the entire dial visible from almost any angle which is a surprisingly cool effect.

24-hour hand. The Scubamaster has four hands: hour, minute, second, and a 24-hour hand. The watch is designed to be able to easily track the time in two different time zones, and to be able to switch time zones quickly and easily. When in you home time zone, you keep the hour hand and the 24-hour hand in sync. When you travel outside your home time zone, the movement is designed in such a way that you can easily adjust the hour hand forward or backward, depending on whether you are traveling east or west. That way, the hour hand indicates the time where you currently are while the 24-hour hand retains your home time.

Bell & Ross has a beauty of a diver called the Hydromax which they claim (and back up with details) will withstand a depth of 11,100 meters, or about 36,500 feet. While not the most extreme of the extreme divers, that still makes it capable of reaching the bottom of Challenger Trench, one of the deepest known points in the ocean. There is, as you might expect, some impressive engineering going on in this timepiece.

In additional to an oil-filled case, the caseback of the watch has a rubber button which helps accommodate the changing properties of the oil under extreme temperatures and depths. The button can become convex or concave as the oil expands or contracts. While I will concede that a $2,400 watch that can go as deep as one of the deepest points in the ocean may be a little overkill, the watch is more of a proof of concept and a brand statement for Bell & Ross professional watches.

Next up is the MTM Black Seal (read the full review here). This one is defiantly worth a few minutes of your time. With an oil-filled case, the MTM Black Seal claims to be completely waterproof to 12,000 meters (39,000 feet), and even adds some interesting features like a high-end Swiss quartz movement, a sapphire crystal (much harder then the mineral crystal found on the Abyss), and Tritium-filled glass tubes on all the markers. Tritium gas is electro-phosphorescent meaning it glows all the time, and the tubes have enough gas to glow for 25 years. This is far more useful then luminous paint because it glows brightly and constantly without the need to charge from ambient light. At $1,800, the Black Seal is a serious watch with a serious look and a very comprehensive set of features.

We now head north from Switzerland (or at least Swiss made) to Germany where the Sinn UX is a serious extreme diver contender. The silicon oil filled Sinn UX is certified to 12,000 meters (39,000 feet) and is built from steel designed for submarines which is five times harder than regular stainless steel.