The Titanium Field Guide

Citizen Promaster Marine Mechanical Diver 200m (NB6021-17E)

The Citizen Promaster Marine Mechanical Diver 200m (NB6021-17E) is a current-production diver watch with a super titanium (proprietary) case, finished with duratect titanium carbide (silver). At 75 g it sits among the lighter diver watches in the guide, and is priced well under the $1,299 median for the category. The maker states no nickel-bearing steel at any skin-contact point, across the case, caseback and bracelet.

All Citizen watchesWatch diver watchesUnder $1,000LightweightLightest, ranked
Price
≈$725 (¥115,500)
Material
Titanium
Grade / type
Super Titanium (proprietary)
Weight
75 g (with strap)
Water resistance
200 m
Type
Diver
Case diameter
41.0 mm
Thickness
12.3 mm
Origin
Japan
Movement
Automatic (mechanical diver)
Caliber
Citizen 9051
Power reserve
Automatic
Complications
Date
Colour
Grey
Surface treatment
Duratect titanium carbide (silver)
Finish technology
Surface hardening
Caseback
Titanium
Nickel-free
Maker states none
Bracelet / strap
Polyurethane strap
Crystal
Sapphire
Display back
No
Dial
Black dial
Dial colours
Black
Lume
Luminous hands and markers
Availability
Offered
Status
Current
Not published
Reference, Lug-to-lug, Hardness, Construction, Matching bracelet
High confidence Verified Sep 2026 Source: Citizen Japan, Promaster NB6021-17E (maker product page)
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Frequently asked questions

Is the Citizen Promaster Marine Mechanical Diver 200m (NB6021-17E) nickel-free?

On the maker's published specification, no nickel-bearing steel touches the skin: a super titanium (proprietary) case with a titanium caseback, plus a non-steel crown and strap. That is what the guide records rather than a test of the watch, so confirm the contact points with the maker before buying if you react to nickel.

What is the case material of the Citizen Promaster Marine Mechanical Diver 200m (NB6021-17E)?

The Citizen Promaster Marine Mechanical Diver 200m (NB6021-17E) has a super titanium (proprietary) case with a titanium caseback. This is confirmed against the maker spec.

What size is the Citizen Promaster Marine Mechanical Diver 200m (NB6021-17E)?

It is 41.0 mm in diameter, 12.3 mm thick, and water resistant to 200 m.

How much does the Citizen Promaster Marine Mechanical Diver 200m (NB6021-17E) weigh?

About 75 g (w/ strap).

How much does the Citizen Promaster Marine Mechanical Diver 200m (NB6021-17E) cost, and is it available?

It is current-production and lists from $725.

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