Seiko Prospex Marinemaster 1000m Hi-Beat SBEX001G Titanium Limited Edition Watch Hands-on

By Meor Amri Meor Ayob

I was elated when I got my hands-on the Seiko Perspex Marinemaster 1000m Hi-Beat SBEX001G Titanium Limited Edition back in August this year. Seiko introduced the SBEX001 piece in March 2015 during Baselworld 2015 with a lot of innovative features. Enthusiasts went wild and all reviews were written have only praises for the watch. With such overwhelming endorsements, I expected every example to be quickly snapped up when Seiko starts shipment. I was made to understand only three examples were allocated to Malaysia. I was the first to get my hands on one when it arrived in Malaysia. Watch number 260 out of only 700 examples in the whole world is now mine.


Shape wise, the SBEX001 is similar to the 300 Marinemaster. It has a monocoque case i.e. the insides can only be accessed via one major opening through the dial side. The screw-down crown is located at the 4 o’clock position. There is a date window and time is shown via a three hand system. Apart from these similarities, the two watches are different like night and day.


The first major difference is size. This watch is big, very big. At 48.2 mm (excluding crown) across and at a height of 19.7 mm, the first assumption is that not everyone can carry this watch with confidence. However, on closer inspection of the watch, there are a few design features that effectively improve the wearing experience. The monocoque case design allows Seiko’s designers to curve the bottom part of the watch to ‘wrap’ around on one’s wrist.


The second major difference is the main material used. Seiko opted for a special proprietary titanium alloy nicknamed Bright Titanium to keep the piece lightweight and coated in a proprietary coating called Diashield, to improve scratch resistance. The bracelet is also made with the same material and protective coating. The weight of the SBEX001G is just 199 grams.

The third major difference is the movement. It is equipped with Hi-Beat 36000 Caliber 8L55 which until now only exclusively used for Grand Seiko watches. The Caliber 8L55 runs at 36,000 vibrations per hour (or beats per hour; bph) or 10 beats per second. The movement is assembled by hand at the Shizukuishi Watch Studio in Morioka, Japan. The power reserve is 55 hours which is impressive considering all that power comes from just one mainspring barrel.


The first obvious thing I love about the watch is the dial design. Finally, Seiko designers heard my feedback on where to place a date window. As you all know, I love symmetry and replacing one of the primary markers for a date window is a definite design flaw for me. The replacement of a primary marker with a date window caused the dial to look asymmetrical. This would not have been an issue if the primary marker was replaced with something of an equivalent ‘weight’. This mismatch creates a visual perception of instability. You won’t find this issue with the SBEX001.


I have been wearing the watch for some time now and despite its size, in my opinion, it wears like a 42 mm watch. Nevertheless, the height of the watch is still something that would be difficult to muster if you want to use the watch with formal wear.

Every time I pick up the watch, I am always surprised by the disconnect between size and weight. It was smart of Seiko to choose titanium as the metal of choice. Any other type of metal and the watch would be too heavy. Moreover, titanium has the ability to withstand the corrosive seawater much better than stainless steel.


Visually, the watch has a lot going for it despite the contemporary design. An example of an interesting visual cue is the bolted-on-bracelet, secured by two screws on each end. The screwed on end-links serve to secure not just the bracelet, but also the bezel. It actually enhanced the rugged look of the watch. Another is the curvature of the watch casing to follow the shape of a wrist. This design goes a long way towards making the watch more wearable despite the size. Instead of just sitting on the wrist, the watch wraps itself on the wrist, making it more stable. Moreover, the side walls are not flat but angled and this helps minimize the possibility of snagging on shirt cuffs etc.


A lot of people have written about the quality of the luminous paint used by Seiko. Using their own proprietary paint formula called LumiBrite, the latest recipe enhancement has been touted by Seiko to glow up to 60% longer than previous versions. Here is a picture of the luminescence generated by the LumiBrite paint on the SBEX001G. The luminescence was so bright that everything close to any LumiBrite painted area can clearly be seen. Mind you, the paint was only charged for approximately 20 seconds using a halogen table lamp.

From my observation, the titanium bezel appears to be coated with either a glossy black ceramic lacquer or ceramic inserts. It is so smooth to the touch and mirror-like. The outer-side of the bezel is gear-like in design for easy of gripping while wearing gloves. I love to manipulate the bezel as it feels solid and there is no looseness.


An interesting point to note is the titanium bracelet. When I read the specification prior to handling the watch, I was worried that this could be the Achilles heel of the SBEX001. From 22 mm across at the end-links the bracelet tapers down to 18 mm at the clasps. The bracelet’s dimensions appear inadequate to support a 48.2 mm wide watch face. However, when I got the watch, my concerns were misplaced. The bracelet is the correct size for the watch. For a professional diver with a bracelet, Seiko provides an in-house ratcheting divers extension mechanism within the clasp. This system makes the clasp look thick. To balance the thickness, the Seiko designers tapered down the bracelet at the clasp. This helps maintain some form of equilibrium throughout the bracelet.

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So, how does it wear? Surprisingly well for a large watch. The use of the lightweight Titanium and the curved casing contribute immensely to its wearing comfort. I had the opportunity to wear the watch with formal wear in the office. Despite the perception that you cannot wear a cuffed shirt with the SBEX001G, in reality, you actually can without any issue of snagging. The angled sides help the watch to easily slip below shirt cuffs. Nevertheless, the height of the watch does make it stand out on the wrist. After a while, it does get tiring if you have your shirt cuffs as well as your suit cuffs pressing on it all day. It is best worn without tight cuffs.

Once you paid a handsome fortune for a watch, you do expect it to be able to fit into your environment. In reality, this watch is a thoroughbred sports watch, made for a professional diver. It can entertain your needs as an office wear or formal wear but only to an extent. It needs to break free from the conformity of rule. It strives on danger. It wants its owner to follow it down to 1,000 meters underwater to see it perform at the extreme edge of its design specification. If you cannot accept this reality, the love you had for the watch at the onset vaporizes quickly. This is the reason why you start to see a few of these watches now available for re-sale.

For me, my interest is the technology. Monocoque case, Hi-Beat caliber, 1,000-meter operating depth without the need of a helium escape valve system, titanium, sapphire crystal with anti-fogging coating and anti-magnetic protection of up to 16,000 A/m (or 200 Gauss).

It has the wrist presence and a slew of the best technologies Seiko can muster at this point in time. A true showcase of Seiko’s 50th year in the dive watch field. For me, it is a keeper. For more info, please visit




Meor Amri is a passionate watch collector from Kuala Lumpur, Malaysia. Having bitten by the horology bug in 2010, he has written extensively about the watch scene and has assembled a large collection of watches (excessively!!!) on his own free time. His blogs on the same subject are: Eastern Watch & Western Watch Read his articles here