Lum-Tec is a US based family run company and their watches are all hand crafted by their team of professional watchmakers.

They produce a variety of styles and models, the 300M being the diver.

There is four versions of the LT300M, I will try to briefly show the differences.

LT300M-1 40mm stainless steel case, 14.75mm thick. Seiko NH35A
LT300M-1XL 45mm stainless steel case, 14.75mm thick. Seiko NH35A
LT300M-2 40mm stainless steel case with Titanium Carbide PVD hard coating, 14.75mm thick. Seiko NH35A
LT300M-2XL 45mm stainless steel case with Titanium Carbide PVD hard coating, 14.75mm thick. Seiko NH35A
LT300M-3 40mm stainless steel case with Titanium Carbide PVD hard coating, 14.75mm thick. Miyota 9015
LT300M-3XL 45mm stainless steel case with Titanium Carbide PVD hard coating, 14.75mm thick. Miyota 9015
LT300M-4XL 45mm stainless steel case, 14.75mm thick. Miyota 9015

Model 1, 1XL, 2 & 2XL can be found easily.
Model 3 – 4XL I have only seen on Lum Tec’s website. Possibly because they are limited and numbered series.

I will just be covering the 1 and 2 series here.


Powering the Lum-Tec LT300M (1 & 2) is Japanaese automatic movement, that being the Seiko NH35.

We have touched in this movement in previous watches on this list so we know that it has hand-winding, hacking, a 40 hour power reserve and the Diashock shock system.


The case is available in two sizes, 40mm being the regular size and 45mm being XL size. Case thickness remains the same at 14.75mm.

Stainless steel is used for all cases but the black versions have the PVD hard coating treatment.

The case back is screw down with the brands intials/logo LT engraved in to it.


On the face is a sapphire crystal with clear double side anti-reflective coating.

Instead of the normal alluminium insert in the bezel it has a sapphire one. The bezel is uni-directional.

The dial iself is quite bold, with a large arabic 12 marking the top postion and tent like markers with cut-outs at the 3,6 & 9 positions. The remaining spaces are marked with bold dashes.

On the outer edge of the black dial is slightly raised chapter ring, giving the dial an appearence of depth. If you look closely you will see a small date window sitting between the 4 and 5 markers.

Notable Features

Lum-Tec is not just a name, it’s part of the watches. These watches put on a show when the lights go out.

What Lum-Tec have developed it something techy called MDV (Maximum Darkness Visibility), which is a special 6-8 layer application of Super-LumiNova applied over a chemical coated white base, causing an incredibly bright luminescent light charge.

When light gets low or night falls the face lights up in an array of green and blue. The dial, chapter ring and bezel all put on a light show that can last up to 24 hours.

Lum- Tec’s automatic dive watches also come with two straps. The standard bracelet with special ratcheting diver’s extension and a rubber strap, should you want a more dive inspired look.

Pricing of the LT300M is fairly constant and sits around the mid 700’s.

Note: if you decide to buy one of these, go to and but one of the 3 or 4 series. For an extra 20 dollars you get the Miyota 9015 movement.


  • Available in 40mm case
  • Super-bright lume
  • Easy expandable bracelet clasp


  • Pricey for a watch with NH35 movement 

(Note: Lum-Tec give free lifetime timing adjustments on their automatic movement watches)

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