The Titanium Field Guide

Heimdallr Titanium MM300 Diver

The Heimdallr Titanium MM300 Diver is a 42 mm Grade 3 titanium dive watch with a Seiko NH35 automatic movement.

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Material
Titanium
Grade / type
Grade 3 titanium
Water resistance
300 m
Type
Diver
Price
– · Not recorded: the listing is on Tandorio's store rather than Heimdallr's own, and its struck-through reference figure is lower than the charged figure on two of three variants, so no credible list price could be read
Case diameter
42.0 mm
Thickness
15.3 mm
Lug-to-lug
49.6 mm
Origin
China
Movement
Automatic
Caliber
Seiko NH35
Complications
Date
Colour
Grey
Surface treatment
None
Finish technology
Natural finish
Nickel-free
Unconfirmed (contact-point materials not all confirmed)
Bracelet / strap
Rubber dive strap with titanium buckle
Crystal
Sapphire
Display back
No
Dial
Green, champagne or black, with date
Dial colours
Black Green Champagne
Lume
C3 Super-LumiNova
Availability
Offered
Status
Current
Not published
Reference, Weight, Power reserve, Hardness, Construction, Caseback, Matching bracelet
Medium confidence Verified Oct 2026 Source: Tandorio store, Heimdallr Titanium MM300
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Frequently asked questions

What grade of titanium is the Heimdallr Titanium MM300 Diver?

Grade 3, from a secondary source. The guide has not yet read the grade on the maker's own page.

What size is the Heimdallr Titanium MM300 Diver?

The case is 42 mm across, 15.3 mm thick and 49.6 mm from lug to lug. It is water resistant to 300 m.

How much does the Heimdallr Titanium MM300 Diver cost, and is it available?

It is in production, but the maker does not publish a price.

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