Hands-On: Citizen Promaster Eco-Drive Professional Diver BN1024-01E
Citizen has updated one of its most popular Promaster Eco-Drive diver models. The BN0150-10E becomes BN1024-01E and has been updated in almost all areas—it’s bigger, goes deeper, is stronger, lasts longer, and is now suitable for professional use. Let’s dive into the details!
For over 35 years, Promaster has stood for functionality and professional use. Citizen’s latest Promaster model is the BN1024-01E, Eco-Drive Professional Diver 300 meters. Equipped with Citizen’s light-powered in-house quartz caliber E365. Fully charged, this caliber has a power reserve of 365 days. The new Eco-Drive Promaster returns to many design elements of its ancestor, the BN0150-10E. There are also a few additional features from other models in Citizen’s Promaster Diver collection. The BN1024-01E is designed as a saturation diving watch and is therefore equipped with a helium valve. Its water resistance has consequently been increased to 300 meters.
Citizen Promaster Eco-Drive Professional Diver BN1024-01E
This hands-on review covers the BN1024-01E. However, Citizen’s new Eco-Drive Professional Diver is available in two dial variations. Inspired by the dark hues of the deep sea, the one we’re reviewing has a gray-black dial. It transitions from gray into a deeper shade at the 6 o’clock position. The other model, with reference BN1024-01Z, sports a dark red gradient dial. Although the red is attractive, in my opinion, the black dial version is the way to go for a professional dive instrument. Both models lack an orange minute hand, as often seen on other Promaster models like the BN1024’s ancestor, BN0150. A feature I find effective in distinguishing the minute hand from the hour hand, especially when wearing fogged-up diving goggles. As expected from a Citizen Promaster, the hands and indices are well-lumed for readability in low-light conditions.
Sapphire crystal
I’ve already given away some key specs, so what are the most notable further elements of the BN1024-01E? Let me start with the glass protecting the new dials and all-white hands. As a result of the increased depth rating of 300 meters, the BN1024-01 is equipped with a four-millimeter-thick anti-reflective sapphire crystal. Sapphire is a big plus for diving watches; their glass can often be subjected to abrasive elements during tough deployment. The sapphire crystal’s thickness easily withstands the 300 meters depth rating (tested to 375 meters as specified by ISO 6425), but also ensures that it doesn’t break when taking a hit. The BN1024’s ancestor had mineral glass, so the sapphire is a nice upgrade.
Stainless steel bezel and insert
It’s a small step from the sapphire crystal to the unidirectional rotating 120-click dive bezel. What I noted first about this bezel is the recessed minute track. The 5-minute cardinal indicators are located on the flat top of the bezel, while the minute points are slightly recessed on the inside. This is a neat solution for quickly reading a rough indication while also being able to perform a more accurate measurement.
The outside of the bezel has a highly grippy serration, applied in a familiar design for Promaster models. According to Citizen’s watch service department, the bezel inlay is printed stainless steel. I would have expected ceramic or aluminum here, or at least a PVD or DLC coating, but probably there’s an advantage to using printed stainless steel. I imagine it might be that stainless steel is more corrosion resistant than aluminum when subjected to saltwater, and less prone to shatter on impact (one of ceramic’s most significant flaws).
365 days of Eco-Drive
Introduced in early 2023, Citizen’s new E365 caliber represented a significant advancement in Citizen’s Eco-Drive technology. The E365 offers a 365-day power reserve on a full charge. The enhancement was achieved through improved power generation efficiency and reduced energy consumption compared to earlier Eco-Drive calibers. This enhanced power reserve is now available in a Promaster Diver for the first time.
According to ISO 6425, the movement must have an end-of-life indication when using a quartz movement in a diving watch. The E365 has this feature. When the energy stored in the rechargeable cell diminishes, the watch indicates this by moving the second hand in two-second intervals instead of the usual one-second steps. This double-tick motion serves as a visual cue that the watch requires recharging through exposure to light. Citizen promises a movement accuracy of plus or minus 15 seconds per month. Meanwhile, it’s generally known that most Eco-Drive calibers perform better than the given specs.
Size and wearability
With a diameter of 46.0 mm and a thickness of 16.3 mm, the BN1024-01E is by no means a small watch—quite the opposite. My wrist size, at nearly 18 cm in diameter, is medium-sized at best. So, this seems like we’re headed for a bad combination. However, nothing could be further from the truth. At the risk of starting another “but this watch wears much smaller” story, I must admit that this is what it is. And it’s partly easy to explain based on an article I wrote about this before.
The case has no lugs, so nothing protrudes outside the 46.0 mm watch case. However, the BN1024-01 differs slightly from a Tuna because of the strap’s shape; I’ll get into that later. First, I want to point out that the real reason the watch is overly present on your wrist is not its diameter but its thickness. It wears very comfortably, even on medium wrists. However, its thickness makes seeing it as a daily wearer questionable.
A Benebiol™ strap
For the BN1024-01E’s strap, Citizen chose Mitsubishi Chemical Group’s world’s only plant-derived polycarbonate diol material, Benebiol. It’s hydrolysis-resistant* and has a lower environmental impact than the regular Citizen Promaster rubber straps. The material is soft and flexible, has a nice feeling, and is comfortable to wear. The shape of the strap, specifically at the end where it fits into the case, is rather pronounced. This shape enhances wearing comfort, but on the other hand, it prevents the strap from bending straight down from the case. Therefore, its fit differs from, for instance, a lugless case like the Seiko Tuna. I also want to mention the strap’s handy widening at the long end, preventing it from unintentionally sliding through the buckle.
*Theoretically speaking, hydrolysis is the process of breaking down a chemical compound that involves splitting a bond and adding water to the resulting molecular fragments. More practically, if a material, like Benebiol, is hydrolysis-resistant, it can withstand exposure to humidity and heat for extended periods of time, without disintegrating
Professional diving
Whether it is often used or not, upgrading from a regular scuba diver’s watch to a professional saturation diver’s watch is a serious enhancement. To achieve this, the depth rating has been enlarged from 200 to 300 meters, and a helium escape valve has been added. Additionally, a saturation diver’s watch has to comply with Annex A, an extra set of ISO 6425 requirements. I’m sure that 99% of our readers and potential buyers of this Citizen Promaster Professional Diver will never be in a saturation diving situation. But knowing that the watch is suitable for it, like other watches, can fly to the moon, is reassuring and pleasing.
Conclusion and pricing
The new Promaster Eco-Drive Professional BN1024-01E is updated in almost all areas compared to its ancestor. It has a higher pressure rating, a sapphire crystal, a helium escape valve, a sophisticated Benebiol strap, and a movement with a better power reserve. So it’s easy to understand that it’ll be preferred over the BN0150-10E. But is that valid for everyone? Probably not, and these are the two reasons. Due to the enhanced specifications, the new Promaster Eco-Drive Diver is larger in diameter and much thicker. Not everyone might favor this. It can distinguish between a watch suitable for everyday use and one not. It is not a big deal if you don’t wear the same watch daily, but otherwise it can be.
Another point that could favor the BN0150-10E over the new BN1024-01E is its price. The new diver has a list price of € 499 including tax. The going price of its ancestor is less than half of that. Still, I think the new BN1024-01E offers a lot of value for the money. What do you think about the Citizen Promaster Eco-Drive Professional Diver BN1024-01E? What are its strong points, and which are its weaknesses? Please let us know in the comments below!
