CITIZEN AT8304-57W PROMASTER ECO-DRIVE CHRONOGRAPH MEN WATCH
AT8304-57W
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- 3 Years Warranty
Pilot's watches carry so many functions that they usually run 43mm or larger. The Citizen Promaster Sky RC 41 exists to prove that isn't necessary. World time across 26 cities, a chronograph, a radio-controlled Eco-Drive movement and an internal slide-rule bezel — all inside a 41mm case.
The timekeeping is radio-controlled: the in-house Calibre H800 picks up atomic clock signals and keeps time to the second, without you ever setting it. Out of signal range it holds ±15 seconds a month on its own. A perpetual calendar, day and date display, 24-hour display and a chronograph timing to 1/20 second across 60 minutes round out the functions.
The slide-rule ring sits inside the crystal, turned by a second crown at 8 o'clock — used for fuel consumption and tank capacity calculations, and protected from knocks by living under the glass. The matte black-coated stainless steel case is 11.62mm thick, with a knurled crown and crown guards, anti-reflective sapphire crystal, magnetic resistance and 200 metres of water resistance.
At a Glance
- BrandCitizen
- CollectionPromaster Sky RC 41
- MovementCalibre H800 Eco-Drive
- TimekeepingRadio-Controlled (Atomic)
- Case Size41mm
- Thickness11.62mm
- Weight153g
- DialGreen
- BezelInternal Slide Rule
- World Time26 Cities
- GlassSapphire, Anti-Reflective
- Water Resistance200m
Why You'll Love It
- This is a full-function pilot's watch in a 41mm case. Most watches with this feature set run 43mm or larger — Citizen built the RC 41 specifically to prove the compromise wasn't necessary.
- Radio-controlled timekeeping means the watch syncs itself to atomic clock signals and stays accurate to the second. You never set it, and it corrects itself when you travel.
- Even with no signal available, the H800 calibre holds ±15 seconds per month on its own — so accuracy doesn't depend on reception.
- The internal slide rule sits under the crystal and is turned by a dedicated second crown at 8 o'clock, so the scale stays protected from knocks and the case keeps a clean profile.
- World time across 26 cities with a recallable time zone makes switching between home and destination time genuinely quick.
- A perpetual calendar handles month lengths and leap years automatically — the date never needs correcting.
- No battery, ever. Eco-Drive runs on light, with a power reserve indicator on the dial so you always know where you stand.
- Anti-reflective sapphire crystal, magnetic resistance, crown guards and 200m water resistance make this a properly engineered instrument rather than a styling exercise.
Perfect For
- Aviation & Pilot Watch Enthusiasts
- Frequent Travellers
- Eco-Drive & Solar Watch Fans
- Atomic Timekeeping Fans
- Full Function, Moderate Size
- Green Dial Collectors
- Gift for Him
Key Features
- Radio-controlled (atomic) timekeeping — synchronises to atomic clock signals for second-level accuracy, with ±15 seconds per month when out of range.
- Internal slide-rule bezel — for fuel consumption and tank capacity calculations, operated by a second crown at 8 o'clock.
- World time, 26 cities — with a recallable time zone.
- Chronograph — 1/20-second increments, measuring up to 60 minutes.
- Perpetual calendar with day and date display, plus a 24-hour display.
- Citizen Eco-Drive Calibre H800 — light-powered, with a 180-day power reserve at full charge and a 10-month reserve in power-save mode.
- Power reserve and charge level indicators — on the dial.
- Green dial — with luminous hands and indexes and a central seconds hand.
- 41mm matte black-coated stainless steel case — 11.62mm thick, 153g, with a knurled crown and crown guards.
- Scratch-resistant, anti-reflective sapphire crystal.
- Magnetic resistance.
- Matte black-coated stainless steel bracelet — safety folding clasp with logo.
- 200-metre water resistance (20 BAR).
Technical Specifications
The Citizen Promaster Sky AT8304-57W is a 41mm men's radio-controlled Eco-Drive chronograph powered by Calibre H800, synchronising to atomic clock signals and holding ±15 seconds per month without reception. The matte black-coated stainless steel case measures 11.62mm thick and weighs 153 grams, with a knurled crown and crown guards, anti-reflective sapphire crystal, magnetic resistance and 200 metres of water resistance. The green dial carries luminous hands and indexes, a world time function covering 26 cities, a perpetual calendar with day and date, a 24-hour display, a chronograph timing to 1/20 second across 60 minutes, and power reserve and charge indicators. An internal slide-rule bezel is operated by a second crown at 8 o'clock. It's finished on a matte black-coated stainless steel bracelet with a safety folding clasp.
| Model Number | AT8304-57W |
| Collection | Promaster Sky RC 41 |
| Case Material | Matte Stainless Steel, Black-Coated |
| Case Diameter | 41mm (excluding crown) |
| Case Thickness | 11.62mm |
| Weight | 153g |
| Bezel | Internal Slide Rule, Second Crown at 8 O'Clock |
| Crown | Knurled, with Crown Guards |
| Glass | Sapphire, Scratch-Resistant, Anti-Reflective |
| Magnetic Resistance | Yes |
| Water Resistance | 200 Metres (20 BAR) |
| Colour | Green |
| Hands & Markers | Luminous, Central Seconds Hand |
| Timekeeping | Radio-Controlled (Atomic) |
| World Time | 26 Cities, Recallable Time Zone |
| Chronograph | 1/20 Second, up to 60 Minutes |
| Calendar | Perpetual, Day & Date |
| Indicators | Power Reserve, Charge Level, 24-Hour |
| Material | Matte Stainless Steel, Black-Coated |
| Clasp | Safety Folding, with Logo |
| Calibre | Citizen H800 |
| Type | Eco-Drive, Radio-Controlled |
| Accuracy (No Signal) | ±15 Seconds/Month |
| Power Reserve | 180 Days at Full Charge |
| Power-Save Reserve | 10 Months in Darkness |
Best Matched With
- Flight Jacket
- Olive Field Jacket
- Technical Outerwear
- Dark Denim
- Travel Essentials
- Smart-Casual Weekend
Frequently Asked Questions
What does "radio-controlled" mean?
The watch receives time signals broadcast from atomic clocks and corrects itself automatically, keeping accuracy to the second without you ever setting it. When you travel, it re-syncs to the local signal. Outside reception range it keeps time on its own to within about 15 seconds a month.
Why is the 41mm case notable?
Pilot's watches carry a lot of functions, so they usually end up at 43mm or larger. Citizen designed the Promaster Sky RC 41 specifically to fit a full feature set — world time, chronograph, radio control and a slide rule — into a 41mm case, for people who want the capability without the size.
How does the internal slide rule work?
The slide-rule scale sits inside the crystal rather than on an external bezel, and you turn it using a second crown at the 8 o'clock position. It's used for aviation calculations such as fuel consumption and tank capacity. Keeping it internal protects the scale from knocks and keeps the case profile clean.
What is a perpetual calendar?
A perpetual calendar automatically accounts for months of different lengths and leap years, so the day and date displays stay correct without you ever manually adjusting them at month-end.
How long does the charge last?
About 180 days — roughly six months — from a full charge with no further light exposure. If it goes into power-save mode in darkness, that extends to around 10 months. A power reserve indicator on the dial shows you where you stand at any time.
What is Eco-Drive?
Eco-Drive is Citizen's light-powered movement technology. A cell beneath the dial converts any light source — sunlight, a lamp, an overhead office light — into energy stored in a rechargeable cell, so the watch never needs a battery.
What does magnetic resistance do?
It protects the movement from the magnetic fields found in everyday objects — laptops, speakers, phone cases, bag clasps — which can otherwise affect a watch's timekeeping accuracy.
Is this a dive watch?
No — it's a pilot's watch from Citizen's Promaster Sky line, built around the slide rule, world time and radio-controlled timekeeping. The 200-metre water resistance means it handles swimming and snorkelling comfortably, but the watch is designed and equipped for flying rather than diving.
Will 41mm fit my wrist?
41mm sits comfortably in the modern men's range and suits most wrist sizes well — that's the point of this model. At 11.62mm thick it's genuinely slim for a watch carrying this many functions, though at 153g on the steel bracelet it has real substance.
Is the bracelet adjustable?
Yes. The bracelet can be resized by adding or removing links. City Chain offers complimentary bracelet sizing at any outlet — bring your warranty book along for the service.
What warranty does this watch come with?
The AT8304-57W comes with a 3-year warranty when purchased from City Chain Singapore, an authorised Citizen retailer. Keep your warranty card and proof of purchase — both are required when submitting the watch for service at any City Chain outlet.
Why Buy from City Chain Singapore
- Authorised Retailer 100% genuine Citizen product
- 3-Year Warranty Covered on every purchase
- Free Shipping All orders within Singapore
- Bracelet Adjustment Size it in-store
Gift With Purchase
Free Promaster Travel Watch Pouch with every Citizen watch purchase. While stocks last.
Extra $15OFF with min. $200 spend
Use Code: 15FORYOU
Extra $30OFF with min. $400 spend
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Caliber: H800
Movement: Eco-Drive
Strap: Stainless Steel
Water Resistant: 200m
Thickness: 11.6mm
Case Size: 41mm
Case: Stainless Steel
Glass: Sapphire Glass
Maximum run time from full charge (Normal Use Condition): Approximately 6 months
Specification
24hrs, Date and Day Display
26 World Cities Time
Chronograph
Eco-Drive
Global Radio-Controlled
Insufficient Charge Warning Function
Luminous Hands and Index
Overcharge Prevention Function
Perpetual Calendar
Power Saving Function
Summer Time ON / OFF
Delivery within Singapore | Order by 11AM
(Checkout options may vary depending on minimum order requirements)
• Free Standard Delivery (3 business days)
• Free Next Day Delivery
• Express Delivery at $30 (order by 2PM)
• Click & Collect (ready in 2–3 business days)
Weekend & Public Holiday Orders
Orders placed during this time will be processed on the next business day.
For online purchase, you can have bracelet or leather strap adjustments done at any City Chain store. Please bring along your warranty book for the service.
