LUM-TEC 300M-1 Dive Watch Review Wrist Time Reviews

Lume on the Lum-Tec 300m

It seems appropriate to start a review of a Lum-Tec with a picture of their namesake. Eight layers of luminous pigment, in blue and green; makes for a spectacular display at night, or even walking inside to a dark room. This is the LUM-TEC 300M-1, introduced in 2013 and available in 40 or 45mm versions, in either brushed stainless or PVD treatment.

This particular watch is the 40mm version, sent at my request. Lum-Tec mainly makes larger watches, so I was excited to check out a size that is more to my liking. This design in particular I like, as the dial and bezel are reminiscent of my now-sold IWC 3568.


The LUM-TEC 300M-1 is 40mm, 41mm at the bezel, and 48.5 lug to lug. Compact and solid, measuring 14.8mm thick with a 5.8mm crown and 22mm lugs. The bracelet is 22 by 4.5mm, non-tapering, with solid end links, one micro adjustment, double-button push release and on-wrist ratcheting extension. The LUM-TEC 300M-1 has a sapphire crystal with double sided anti-reflective coatings. The 60-click bezel has a sapphire insert with backside lume, a nice combination of luminosity and scratch resistance. Weight is 96g for the watch, 120g on the rubber strap and 215g on the bracelet.

LUM-TEC 300M-1 Dive Watch Review Wrist Time Reviews

Lum-Tec 300M-1

The movement is interesting: It’s a SII NH35, which is Seiko’s OEM version of the 4R35. SII lists it as an upgrade from the NH25, and it seems to be finished better. Automatic, with handwinding and hacking, it runs at 21,600vph (3Hz) versus the 28,800/4Hz 2824 or Miyota 9015. Twenty four jewels, quickset date, and a power reserve in excess of 40 hours. All of those are  good, but what makes it exceptional here is Lum-Tec’s preparation of it: they adjust it to six positions for accuracy and offer free lifetime timing adjustments.

That’s phenomenal, and unheard of for a watch in this price range. Clearly, Lum-Tec has enormous confidence in this movement. Personally, I’ve had 3 SKX-series divers with variations of the 7S26, and they all had very poor accuracy and even worse isochronism. Even the 8L35 in my Marinemaster was worse than most ETA 2824s, so I was pessimistic that the NH35 would perform well. The results have been so good I’ve spent extra time verifying them. This watch runs a solid 2-3 seconds slow per day, whether worn, on the winder or even on a desk. Superb performance regardless of orientation, wind state or activity. Bravo indeed!


The packaging is very nice, solid wood with an inset metal logo.

LUM-TEC 300M-1 Dive Watch Review Wrist Time Reviews

Lum-Tec 300M watch box

Inside you’ll find the watch and an additional rubber strap with machined buckle.

LUM-TEC 300M-1 Dive Watch Review Wrist Time Reviews

Lum-Tec 300M rubber strap

The underside of the strap has unusual raised edges and texturing, presumably to let it breathe better on hot days.

LUM-TEC 300M-1 Dive Watch Review Wrist Time Reviews

Lum-Tec 300M rubber strap

The bracelet is very nice, I like how the links are rounded a bit.

LUM-TEC 300M-1 Dive Watch Review Wrist Time Reviews

LUM-TEC 300M-1 bracelet

The bracelet has solid end links, though the machining here is a bit rough.

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