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Diver Watch Hands on:  Seiko Prospex Monster Brothers
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Diver Watch Hands on: Seiko Prospex Monster Brothers

Why you should pay attention to perks of SBDY037 & SBDY035 Seiko's diver watches.

Mar 22, 2021

Seiko is the oldest watchmaker in Japan, dating back to 1881. They brought not only the first quartz watch to the market but also the first automatic chronograph. It was Seiko's dive watch, that was one of their areas of greatest strength.

Introduction: Philosophy of the Name

The original watch that earned the nickname "Monster" from the fans of Seiko was released less than 20 years ago, quickly becoming a favorite in the fan community for its provocative design featuring sharp angles and bold tones. One popular model has a bright orange dial with a fang-like hour marker; Another memorable design is labeled "Dracula" for the use of red accents that stand out on the black dial. The nickname is more than just an affectionate term, as this watch fits the dive watch collector who craves a watch with real tool appeal, rather than the inherent sleekness and refinement found on so many contemporary dive watches. Seiko has recognized Monster's collectability over the years, updating the watch in a variety of designs to attract collectors of all kinds. Its most recent renovations took place last summer with the announcement of the SBDY037 and SBDY035, two dive watches that pick up many of the classic aesthetic features that characterized the Monster during its production life, while changing some of its major design options when the watch is closed. second decade of existence.

 Seiko Prospex Monster SBDY037

 Seiko Prospex Monster SBDY035

When I first encountered Monster, it was an orange oddity with a large triangular hour marker reminiscent of a shark's tooth, and literally the size of a monster, with visually exaggerated dimensions as a result of the distinctive veiled bezel array. Today's monsters are completely different beasts. While still a hefty dive watch, the edges aren't quite as rugged as the original Monster, which remains popular and has become quite collectible in many variants. The current Monster lineup is slightly slimmer and smoother, and doesn't have the same facial styling as the original.

In 1965, Seiko developed the world's first computerized diver's watch, the first Japanese diver's watch. The M726 with dive table and depth gauge functions in 1991, and have continued to make many more over the years. From 62MAS to SKX007 to Tuna to Turtle to Monster to special PADI editions - it's safe to say that Seiko is a legend in the field of diving. Their reputation for making diver's watches is practically unmatched - with a few exceptions.

Case of the Seiko Prospex Monster

The new Monster line (fourth generation), which consists of the Seiko Prospex SBDY037 and SBDY035 Automatic Divers, is slightly smaller, has better ergonomics, and an overall more sophisticated display than the previous generation.

One of the most well-known new design elements is the single-piece (monoblock) stainless steel bezel. From the smoother notches to the sunken circular matte finish to the black PVD top to the polished black PVD edges - everything about the new bezel is smoother.

This refined design language also carries over to the third-generation Monster-like crown, forgetting the knurled surface of its predecessors in favor of a more traditional serrated crown that sacrifices some grip for a refined appearance.

A stainless steel case and bezel measuring 42 mm in diameter by 14 mm thick with day / date cyclops height included (without 12 mm). It makes you wonder if cyclops are even needed, and perhaps for some purists whether that day / date is needed at all. The lug for carrying the case measures 47.5 mm, which is a good length, and in comparison, the same length as the Turtle. However, the Turtle is 44.5mm in diameter so this creates a thinner watch, which may seem strange at first, but eventually after some time using it, I found the aesthetic to be quite interesting.

With a steel band, the reference SBDY037 weighs 186.9 grams, and the rubber strap version, reference SBDY035, weighs 117.37 grams. The interlug width is 19 mm in both. The band feels sturdy and comfortable and the rubber strap feels more comfortable with its soft material. The bracelet has a push-pin safety attachment, 4 micro-adjustments on the clip, and a 2-button safety lock. Perforated lugs offer a more convenient way to replace straps or bracelets compared to solid lugs. Although when replacing a stainless steel bracelet you have to be careful as the integrated curved end connection makes replacement of the bracelet more difficult. There are special clamp-type spring rod tools that are preferred for this type of bracelet, or it may be best to exchange them for a watchmaker. Changing the rubber band feels easier with the pin end of the spring bar tool standard.

This is a genuine "diver" watch that complies with ISO 6425 and is suitable for scuba diving. The 7mm crown is a great size for adjustment but its location at 4 o'clock prevents it from getting onto your wrist. The crown is screwed to the frame and protected from water by two gaskets. There is no traditional crown protector, but there are two metal parts that serve as the bezel protectors which are often referred to as shrouds. The bottom is parallel to the case and appears sufficiently to protect the crown (Seiko Tunas has a full 360 degree shroud).

Solid steel threaded back case is protected from water with gasket. A dense flat Hardlex mineral crystal protects the dial, which is also covered by a gasket and rises just above the plane of the bezel. With 120 clicks, the monoblock one-way stainless steel dive bezel features an elapsed timer bezel for diving and rotates precisely in one direction with two clicks per mark. There's a millimeter or so of wobble in the bezel that's unusual and we've seen significantly more wobble on watches that cost four times their price. The feel of the bezel rotation is pretty good.

Being a 200 meter "diver" watch that meets all the requirements of an ISO 6425 dive watch, this watch is rugged, shock resistant and can withstand water pressure of at least 656 feet. This is twice the standard depth required by ISO, but is usually preferred for professional scuba watches.


Seiko's workhorse caliber 4R36 movement sets the hours, minutes, seconds, and date, and is the same as those found on the Shoots, Turtles, and Seiko 5s. Even though it is not of the newest 6R line, and the power reserve and accuracy are not that high, the cost is still reasonable.

This movement measures 27.4mm x 5.32mm, ticks at 3Hz (or 21,600 vibrations per hour), features 24 gems, 41 hours power reserve, and is equipped with an auto winding rotor with the ability to wind manually too, which is great. considering that not all watches at this price point offer automation with a winding hand. Seiko caliber 4R36 was first released in 2011 and offers a "hack" (the ability to stop the balance wheel by pulling out the knob to adjust the seconds hand precisely). It also offers a quickset day / date with a custom position on the crown and rotates in one direction for that day and in another direction for the date. There are even blue and red colors for Saturdays and Sundays, and a choice of English or Spanish. The date changes gradually (slowly rises before midnight) as opposed to changing in a few minutes (semi-instant) or a few seconds (instantaneously).

One of the biggest differences in performance between this movement and the Swiss movement is the degree of accuracy, with regard to cost and the fact that it may not be overly adjusted when taken out of the factory. The rate is stated as -35 / + 45 seconds per day, compared to the chronometer which is -4 / + 6.Thus, this movement may lose more time and gain more time, but it is accurate enough in the end that you never go more than 2 -5 minutes, according to our experience. As for diving, you won't see much difference at all between this and the chronometer if you calculate the dive time for 60 minutes.

The Dial

The dial has been given a more premium aesthetic, similar to the third-generation Monster but with a wider index and a new sunray dial, including a blue gradient version, similar to the event. The old signature of the Monster dive watch is the shark tooth watch marker, which has been replaced by a more traditional rectangular marker, a first for a third generation Monster. Fortunately, the 12 o'clock marker is still reminiscent of previous generations with shark teeth.

The dial comes in sunshine blue or black, the former having a slight gradient which means it fades from light to dark. In this case, it is darker in the center and lighter at the perimeter. Both look great, while black looks pretty consistent in most lights, blues tend to vary under different lighting conditions, which is probably the end result of a gradient.

Hands are heavily oiled so they are easily visible even under water in dark or cloudy conditions. Compared to the previous model, this modern version features vertically brushed steel hands for a slightly more luxurious look compared to the two-tone paint and blue. Apart from the minor reshaping, the hand was very similar to the one seen on the previous model.

There is an arrow-tipped center seconds hand, a large arrow-tipped hour hand, which is rather short and may be extended to increase readability without sacrificing total design coherence. For the minute hand, such as the middle seconds hand, the hand runs all the way to the starting edge of the flange, which is the perfect length, making the minutes and seconds readings perfect when combined with the new rectangular luminous hour markers applied. , including the double marker shark tooth style at 12.

While purists tend to want a day / date-free dial and a magnifying glass, this feature has been beneficial to some. Overall, the new dial carries on the old lineage but with an evolved modern appearance. When it comes to the lume, it is very bright and has been applied consistently across the markers, hands and large bezel points, as you would expect from any Seiko diver. This is important not only for appearance or simply for viewing in dark environments - it has to be highly visible underwater to meet the strict ISO 6425 "Diver" watch specifications.

Price and Perks

Seiko Prospex Monster Double Black Vintage 200M Automatic Ref. SBDY037 costs around $580.00 USD on Gnomon store and is highly durable and features premium finishes, is at the top of the Seiko watch hierarchy. Then there is the new Seiko 5 which is durable and waterproof but not for scuba diving nor is it marked as "diver" as it lacks certain features and is not tested to ISO 6425 standards, starting at $ 295. Right between the two is the very line of Monsters. 

At $420.00 USD, Seiko Prospex Monster Black Vintage 200M Automatic Ref. SBDY035, with a blue gradient dial looks like a no-brainer. The bracelet is well-made, has four micro-adjustments (which require a tool to adjust), and a robust signed folding buckle with push-button safety release, although there is no diver extension.

As for the rubber strap version, the $160 savings aren't that much, however, the rubber strap is significantly lighter, super soft which makes it very comfortable, and stretchy so it can be worn over a wetsuit. Additionally, the steel buckle and guard are both engraved with the Seiko logo, machine beveled and polished edges on the brushed guard. Other than that, you can't go wrong with a black dial, black bezel, and black strap - there's something about that classic look.

In the end, the blue gradient dial color, which varies between black and blue depending on the light, got me interested, and the bracelet looks really sharp with that combination. Nevertheless, I really like the comfort, functionality, aesthetics, and reliability of the rubber accordion strap, so I would probably go for the blue dial version and add the factory rubber strap separately.

Whether you like a blue or black dial, or prefer a rubber strap or steel band - for five hundred dollars or less, there are few mechanical diver's watches that can compete with it apart from other Seikos. With this latest generation, Seiko has clearly perfected the entire design of the sect's favorite Monsters - both visually and functionally - without significantly increasing prices.

Explore more collections from Seiko: Gnomon Special Highlight This Week: Seiko 5 Sport Lineup

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