ArmourLite IsoBrite Master Diver

The last time I reviewed an ArmourLite it was 2014 and the subject was the IsoBrite ISO100 tactical watch (now christened the Valor Series). I enjoyed that carbon-cased, tritium-tubed beast, so when they told me they had some new models, I had to give them a whirl. For this review, they lent me a stainless steel Master Diver ISO501 on a 22mm solid link bracelet, as well as the black nitrile rubber strap from model ISO503.  

ArmourLite likes their watches on the big side (their smallest model is the 42mm Grand Slimline), and the Master Dives is no exception. Its stainless steel case is 46mm wide, 55.7mm long, and 14mm thick. It's a whole lotta watch, but I wasn't about to let a little extra mass ruin my fun. I gave it a go, putting the watch through its paces for a weekend at the shore, as well as a few days with khakis and a button-down at the office. 

The first thing I noticed was the weight. I am no stranger to heavy diver's watches, and I don't generally worry about it. After all, unless it is made from depleted uranium, a watch can only be so heavy, but this one was heavy enough to send to the postage scale for a reality check. Sure enough, the Master Diver topped 8 oz. on its bracelet. It is certainly noticeable, but not at all uncomfortable. I mean, I'm one of the least fit people I know, and even I have no problem carrying a few extra ounces on my wrist, but if weight is an issue for you, then you will be happier choosing the rubber strap, which drops the watch to a more manageable 5 oz. 

As the name implies, the Master Diver is more than ready for subaquatic excursions. It is rated for 300m water resistance and features an anti-reflective sapphire crystal and knurled screw-down crown, in addition to a 90-click, unidirectional timing bezel cast in high relief. Like all IsoBrite watches, it uses T-100 Tritium tubes for nighttime illumination. While not quite as bright as the best photoluminescent materials, tritium is more than sufficiently potent and offers the distinct advantage of being self-sustaining. The tubes are filled with tritium gas that emits electrons as it decays. When the electrons bounce off the phosphor, they produce a steady glow that lasts for decades. 

The tubes are set into an expansive, wave textured, black dial. They also grace the Planet Ocean style arrow hands and the paddle second hand. Finally, one tiny tube acts as a bezel pip. Leaving nothing to chance, they added spots of lume as well. It's really the best of both worlds; the conventional lume pops to life with its initial light charge, and as it fades, the tritium provides perfect clarity all night. As illustrated below, the tubes don't actually get brighter, but your perception of them does, tricking your eye the same way it tricked my iPhone camera. 

I've just got one hit to pick on the dial and that's the IsoBrite logo. The red and black banner is attractive enough in and of itself, but it is pretty darn big, even on a watch of this size. It didn't faze me on the black carbon Valor, but on this one, it's just a little too much. As the IsoBrite line expands beyond field and sport watches, they might want to consider toning down the logo, or better still, using the stylized "ib" like that embossed on the black crown head. 

There is a host of different finishes at play on this watch. The case is polished, as is the bezel's coin edge. The high points of the bezel are brushed while the insets are matte black and pebbled. Finally, the bracelet is brushed with twin black stripes flanking the center links. Given my druthers, I would have preferred a more uniform approach. Perhaps a brushed finish all around without the black accents, or a combination of bushing and polishing on both the case and bracelet. I was skeptical about how the brushed bracelet would look against the polished case, but it ties into the bezel's satin surface. I am concerned about how the black stripes will hold up as they appear to be painted on. Stripes aside, the bracelet is a quality piece, rock solid with screwed link pins. These are double-ended, requiring a screwdriver in each hand, which is hardly my favorite maneuver, but I managed the job without drama, dropping it down to fit my 6.5" wrist with links to spare. ArmourLite says it will fit wrists up to 9.75" so there is more than enough range of adjustment for everyone. Micro adjustments on the signed flip-lock clasp don't hurt either.

The Master Diver uses a Swiss Ronda Normtech 715Li, a five jewel, lithium powered quartz with end of life indication. It may not be as sexy as a Swiss automatic, but it will best its mechanical rivals in shock resistance, anti-magnetic properties, cost, and accuracy. True, you will have to change its battery, but only once every ten years, which is longer than the service interval for a mechanical watch. 

In my rigorous field testing (drive to office, sit at desk, drive home, repeat) I found the watch to be perfectly comfortable despite its mass. I preferred the bracelet's appearance but the vanilla scented nitrile rubber was a pleasant option. It was softer than the polyurethane often found on most inexpensive divers but did not collect lint like silicone. ArmourLite sells the Master Diver for $539 on rubber, and $580 on the bracelet. While it's nice to have a lower cost option, I always recommend you buy the factory bracelet, and this is no exception. It is well worth the extra $40 to have a bracelet that was tailor made for your watch. Of course, I couldn't let the watch pass through my hands without trying a strap of my own. As I predicted, it looked right at home on sturdy leather like the gator print Crown & Buckle pictured here.

The Master Diver is a competent watch, and the tritium/photoluminescent glow can't be beat, but I suspect most buyers will make their choice based on size and looks. This is not a subtle watch, and while I could wear it without complaint, it was a monster on my 6.5" wrist. It is really best suited for someone larger. I asked a friend who is about 6'2" to try it on his 7.5" wrist, and the proportions were much better. What was comically oversized on me looked perfectly appropriate on him. The Master Diver is a big 'un, but there is a large segment of the watch buying population for whom this is just the thing. 

For more information or to place an order see

Pro: Big! Excellent lume.
Con: Big! Busy design.
Sum: Heavy metal

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