The Citizen Promaster Diver Fujitsubo NB6021-17E is an automatic 200 m diver with a lightweight titanium case, sapphire crystal and Citizen’s Caliber 9051. Its appeal is a mix of practical specifications and vintage-inspired design: “Fujitsubo,” Japanese for barnacle, recalls Citizen’s story of a 1977 diver found covered in barnacles and still running. The specifications below are manufacturer-listed; they are not results from an independent test of a watch sample.
What the NB6021-17E is
Citizen identifies the NB6021-17E as a Promaster ISO DIVER 200M. It is a mechanical automatic watch, not a battery-powered quartz model. Citizen lists automatic and hand winding, hacking seconds, a date display and approximately 42 hours of power reserve for its Caliber 9051 movement. The US product page lists a stated accuracy range of -10 to +20 seconds per day.
That accuracy range is a nominal specification, not a promise that every watch will keep time within those limits in every wearer’s daily routine. In its launch announcement, Citizen describes the figure as average daily accuracy measured in a static state and says actual performance can vary with wearing time, position, arm movement and winding.
Citizen’s listed specifications
| Specification | Citizen’s listing |
|---|---|
| Movement | Caliber 9051 automatic mechanical; hand winding, hacking seconds and date |
| Power reserve | Approximately 42 hours; Japan page specifies maximum-wound running time |
| Case width | 41 mm on the US page; 41.0 mm on the Japan page |
| Case thickness | 12.3 mm, Japan product page |
| Weight | 75 g, Japan product page |
| Case material | Super Titanium with Duratect titanium carbide treatment noted by Citizen |
| Crystal | Sapphire |
| Strap and width | Polyurethane strap; 20 mm lug/band width |
| Water resistance | 200 m / 20 bar; Citizen identifies it as an ISO diver |
| Magnetic resistance | 16,000 A/m, as stated by Citizen for Caliber 9051 |
| Stated accuracy | -10 to +20 seconds per day on the US page; Citizen characterizes the movement figure as a static-state average |
The US and Japan pages are useful for different details: the Japan page supplies thickness and weight, while Citizen’s US page lists the accuracy range. Regional pricing and availability can differ. The Japan page lists ¥115,500 including tax and currently marks the item out of stock; that is a Japan-specific, time-sensitive listing, not a universal price or stock report. Check Citizen’s US product page and Japan product page for current local details.
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What the Fujitsubo name and design refer to
Citizen says the watch’s design draws on its 1977 automatic Challenge Diver. According to Citizen’s account, that watch was found at Australia’s Long Reef Beach in 1983 after years in the Pacific, covered in barnacles and still ticking. “Fujitsubo” means barnacle in Japanese, which explains the nickname. The discovery story is Citizen’s historical account, rather than an independent durability test of the NB6021-17E.
The new model’s vintage reference is therefore more than a name: Citizen connects its styling to the earlier Challenge Diver. Monochrome Watches likewise described the design as 1970s-inspired in its video review published 2022-09-30. That is the publisher’s design impression, not a specification.
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Titanium, size and wearing expectations
Citizen lists a 41 mm case, 12.3 mm thickness and 75 g weight for the Japan-market specification, along with a 20 mm polyurethane strap. Those figures give a useful basis for comparing dimensions and materials, but they cannot establish how the watch will feel on a particular wrist. Monochrome Watches called it lightweight and comfortable in its review description; that is an attributed reviewer impression, not a comfort measurement applicable to every wearer.
Citizen describes the Super Titanium case as treated with Duratect titanium carbide and touts its scratch resistance. The presence of a hardening treatment does not mean the case is scratch-proof. Likewise, sapphire is the listed crystal material, not evidence that the whole watch is immune to damage.
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How to interpret the dive and magnetic claims
200 m water resistance and ISO diver status
Citizen specifies 200 m / 20 bar water resistance and calls the model an ISO DIVER 200M. Its launch announcement says ISO diver-watch requirements are intended to help ensure diver safety. Those are manufacturer claims; no specific test certificate or independent water-resistance test of an NB6021-17E sample is established here. The 200 m figure alone should not be treated as permission for every underwater activity or as a substitute for following the watch’s instructions and keeping it properly maintained.
16,000 A/m magnetic resistance
Citizen says Caliber 9051 uses anti-magnetic materials in the hairspring and other components and meets second-class magnetic resistance of 16,000 A/m. Its launch announcement further says performance is maintained at a distance of 1 cm from equipment emitting magnetic fields. These are Citizen’s stated design and performance claims, not results from independent testing of a particular watch.
Rank #4
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What this video review can and cannot establish
Monochrome Watches’ video description, published 2022-09-30, calls the Fujitsubo “Lightweight, extremely comfortable, good-looking, and a genuine performance bargain.” Those words convey the publisher’s overall impression; they are not measured findings. The available information does not establish the reviewed sample’s accuracy, bezel alignment, lume duration, strap durability, long-term service cost or real-world dive performance. Treat those questions as unresolved unless the video itself documents a specific test and its conditions.
For a comparison with another diver, focus on like-for-like details: case material, diameter, thickness and weight; movement type and reserve; stated accuracy and magnetic resistance; the exact water-resistance and ISO claims; supplied strap or bracelet; and local price, service and warranty terms. The listed specifications make the NB6021-17E a distinctive titanium automatic, but they do not by themselves prove it outperforms another watch.
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Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Sources
- Citizen US: NB6021-17E product specifications
- Citizen Japan: NB6021-17E specifications, price and availability
- Citizen global: Promaster NB6021-17E and magnetic-resistance description
- Citizen: 2022 launch announcement and movement claims
- Monochrome Watches: video review description, published 2022-09-30
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
