Citizen Eco Drive Professional Divers BJ8050-08E Watch Review

The Citizen BJ8050-08E is a divers watch that is part of Citizen's Promaster Sea Collection and meets ISO 6425 regulations. 

The BJ8050-08E is also known as the EcoZilla as it's a large watch. It has a very heavily textured bezel, with large phosphorescent hands, and bold second markings. It has a black dial and non-reflective mineral glass allow that's easy to read in dark conditions.


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Citizen Promaster Professional BJ8050-08E 
- At a Glance

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    48 mm case with 6mm anti-reflective curved mineral crystal display
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    316L Stainless steel casing
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    Solar powered Japanese quartz movement with analog display
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    ISO 6425 certified and water resistant to 660 ft (200 m)
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    Dark Blue dial face with luminous hands and hour markers
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    Eco-Drive technology is fuelled by light and never needs a battery replacement
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    Unidirectional blue bezel
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    Black polyurethane rubber strap with ripples

What's in the Box?

The Citizen Eco Drive Promaster Professional BN0151-09L has a very large, rugged and extremely well-made round case. The case is stainless steel case measuring 48 mm across with a thickness of 12mm. It weighs 1.3 pounds making this a very heavy watch. It measures 1.9 x 0.7 x 1.9 inches

The BN0151-09L has a very distinctive dark blue background on the watch face and blue Polyurethane rubber strap with a stainless buckle clasp. Just like the Seiko SKX series of watches, the Citizen Eco Drive crown is located at the 4-o'clock position so it doesn't dig into the wrist. 

The lugs of the Citizen BN0151-09L measure 20 mm across making it easy to customize with other watch bands.

Citizen Eco-Drive Men's BN0151-09L Promaster Diver Watch

What does ISO 6425 certification mean?

There are many watches available that claim to be divers watches but this is often more about the look of the watch, rather than whether they're actually suitable for scuba diving.

To meet ISO 6425 certification means the watch must meet the minimum safety standards that applies to all diving watches. The Citizen Promaster BN0151-09L is a true divers watch that meets the ISO 6425 standards.

The Bezel

As part of ISO-6425 safety precautions, the BN0151-09L has a stainless steel bezel that becomes slightly harder to rotate when underwater. This is to minimize the chances of it moving accidentally if knocked. The bezel is unilateral, meaning it can only be turned in one direction. 

The BN0151-09L bezel is heavily notched and shows up to 60 minutes of elapsed time. This has a ratchet mechanism so you can hear audible clicks as it's turned. Each click represents half a minute giving you a precise measurement as it's rotated. The zero marker shows the starting point and it has the classic minute markings, with ten-minute markings.

The Crown

The Crown is for setting the time only and is located at the 4 o’clock position. The crown must be screwed in fully to prevent moisture from entering the movement area. Never pull the crown out when underwater, or when the watch is wet.

Turn the crown from time to time to prevent corrosion. This also helps maintain the flexibility of its gasket.

What's the difference between WR200 and Divers ISO 6425 watches?

True Divers watches are designed to ISO 6425 specifications making them suitable for scuba diving. Divers Watches go through more severe water-resistance tests than WR200 watches including pressure tests. 

WR200 watches are designed for the people who enjoy water activities and like to wear a watch that isn't going to become unusable if it gets wet. Water resistance is suitable for water sports or wearing in the surf. 

The stainless steel casing of the Promaster BN0151-09L protects against the corrosiveness of seawater. This classic divers watch has a rich blue rubber strap with ripples to allow flexibility and a good fit when wearing over wet suits and dry suits, or under compression. 

What is Citizen Eco Drive technology?


Citizen Eco-Drive technology uses both artificial and natural light to generate power. Eco drive watches convert light energy into electrical energy using a micron-thin disc of amorphous silicon underneath the dial. The electrical energy is stored in a rechargeable titanium lithium ion battery. 

Citizen eco drive batteries don't use the caustic chemicals used in ordinary batteries, making these batteries much kinder to the environmental.

Recharging the Battery

Exposing the watch to ambient light on a daily basis is generally enough to keep the battery charged. If there is insufficient charge, the second hand jumps in 2-second intervals. As soon as the battery is fully charged, the second hand resumes normal operation.

Recharging can vary depending on the season. Generally speaking, the time required for recharging will be longer in Winter compared to Summer when the illuminance of the sun is weaker. Also, in Winter watches tend to be kept under sleeves of jackets and overcoats which reduces their exposure to natural light.

It's recommended you expose your Eco-Drive to the sunlight or another light source from time to time during Winter months. If you use an artificial light source to charge, make sure it's placed at least 20 inches (or around 50cm) away from the source so it doesn't become overheated.

Citizen Eco-Drive Men’s BN0151-09L Promaster Diver’s Watch

Helpful Tip:  Eco-Drive watches charge in one third of the time if you pull out the crown while charging under normal charging conditions.

How long does an Eco-Drive battery last?

Eco drive watch batteries don't need to be replaced. Citizen factory engineers suggest that even after 20 years of use, each battery will still have around 80% of its ability to be recharged.

The Watch Band

The Citizen Eco Drive Promaster Professional BN0151-09L comes with a dark blue polyurethane band that has Dive Tables No Deco limits printed on one side. It's a well made, soft band that is ribbed so that it fits firmly over a wet or dry suit when scuba diving. This is a classic divers watch style band. 

The lug width is 20mm which is a common size making it very easy to personalize and swap out different band types.

What about Maintenance and Servicing?

As gaskets and gears age and deteriorate over time, a service by a qualified watchmaker or authorized Citizen Service Center is recommended every 2 to 3 years. Regular servicing will extend the life of the watch.

Citizen Eco-Drive Men’s BN0151-09L Promaster Diver’s Watch

The Conclusion?

The rubber strap of the Citizen Eco Drive Promaster Professional BN0151-09L is comfortable and easily supports and compliments the heavier face nicely. The blues of the watch face, bezel and band are nice and rich and the illumination on the hands and hour positions is good, and very easy to read at night.

This is a large, heavy classic Mens Diver's watch. The case has a brushed aluminium look and it stands up well in comparison to its more expensive competitors. A truly beautiful watch.

Citizen Eco-Drive Men's BN0151-09L Promaster Diver Watch
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    Nathan Taylor

    Nathan Taylor is an avid motorbike rider and has enjoyed riding since his early teens. He enjoys hiking and is also a qualified Scuba Diver (Advanced Open Waters).