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Citizen Eco-Drive BM8240-11A Silver Dial Day-Date Classic Leather Watch
- Brand: Citizen
- Product Code: BM8240-11A
- Availability: In Stock
£139.00
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Citizen Eco-Drive BM8240-11A Silver Dial Day-Date Classic Leather Watch
The acquisition of a brand new Citizen timepiece requires a definitive technical understanding of electronic efficiency, materials science, and structural architecture. This factory-fresh Citizen BM8240-11A analogue specimen features light-powered solar calibration and traditional chassis geometries, analyzed thoroughly at our Totnes workshop to verify its authentic performance thresholds and mechanical capability. This comprehensive breakdown serves as an evaluation file similar to the standard layouts observed in documentation across our technical library.
Power Source
180 Days
Eco-Drive Solar Cell
Crystal Optics
Flat Profile
Heavy-Duty Mineral Glass
Water Rating
30 Metres
3 Bar Hydrostatic Limit
Product ID
BM8240-11A
Official Citizen Model
Total Mass
48.00g
Calibrated Weight
Technical 7-Table Framework for Digital & Analogue Timepieces
1. Electronic Movement & Module Specification
| Component | Technical Core | Verification Parameter | Status |
|---|---|---|---|
| Integrated Circuit | Citizen Calibre E101 Eco-Drive | Frequency Stability Analysis | Confirmed Factory Specification |
| Oscillator | Quartz Crystal (32,768 Hz) | Monthly Drift Quantification | Verified Within Limits |
| Display Driver | 3-Hand Analogue Stepping Motor | Mechanical Alignment Check | Optically Clear |
Table 1 Analysis: The watch movement features a dedicated light-powered solar quartz module running on an optimal quartz frequency. This electronic architecture minimizes parasitic power leakage, enabling high-performance timekeeping functions without premature voltage drops across the internal micro-circuits.
2. Dimensional & Geometric Layout
| Dimension Metric | Value | Tolerance Range | Ergonomic Stance |
|---|---|---|---|
| Case Diameter | 36.0mm | +/- 0.05mm | Balanced Horizontal Wrist Footprint |
| Lug Width (Transverse) | 18.0mm | Uniform Edge-to-Edge | Mid-Size Profile Suitability |
| Case Thickness (Z-Axis) | 8.5mm | Consistent Center Point | Low-Profile Cuff Integration |
Table 2 Analysis: Micro-caliper measurement confirms an 8.5mm case depth. The dimensional configuration splits physical mass evenly across the 36.0mm plane, ensuring the 48g unit remains centered over the wrist's anatomical pivot point during physical acceleration.
3. Materials Architecture & Physical Hardness
| Chassis Element | Material Foundation | Mechanical Advantage | Structural Focus |
|---|---|---|---|
| Main Case Body | Polished 316L Stainless Steel | Impact Energy Absorption | High Lustre Execution |
| Case Back Interface | 316L Stainless Steel | Hypoallergenic Contact Profile | Dust Perimeter Guarding |
| Strap Assembly | Genuine Bovine Leather Strap | High Flex-Fatigue Resistance | Ergonomic Wrist Wrapping |
Table 3 Analysis: The polished 316L stainless steel finish balances hardness with historic density. Unlike rigid lower-grade alloys that transmit shock vectors directly to inner electronic components, this surgical-grade steel enclosure cushions the quartz module substrate by dampening mechanical impacts.
4. Optoelectronic Crystal Engineering
| Optical Shield | Geometric Profile | Refractive Index | Stress Threshold |
|---|---|---|---|
| Dial Protective Glass | Flat Mineral Profile | Optimized Transmittance | High Fracture-Shatter Resistance |
| Material Grade | Hardened Mineral Crystal | Mohs Scale: 5.5 - 6.0 | Elastic Flex Under Direct Force |
Table 4 Analysis: The hardened mineral glass geometry introduces a calculated flat layout across the face. This structural setup helps distribute perpendicular surface forces laterally toward the outer bezel, reducing the risk of a focal-point fracture when the watch face takes an impact.
5. Hydrostatic Sealing & Environmental Rating
| Sealing Zone | Mechanism Type | Pressure Certification | Environmental Envelope |
|---|---|---|---|
| Caseback Interface | Pressure-Fitted Backplate | 30 Metres Static Depth | Splashes / Rain Surface Compliance |
| Setting Crown | Gasket Sealing Shaft | 3 Bar Static Load | Atmospheric Moisture Defense |
Table 5 Analysis: Hydrostatic barrier integrity is achieved using a snapped steel caseback configuration. This maintains continuous pressure on the elastomer gasket ring, keeping the dry internal module chamber safely isolated from liquid entry up to a static pressure limit of 3 Bar.
6. Metallurgical Backplate & Fastener Integrity
| Metal Component | Alloy Identification | Corrosion Resistance | Biocompatibility Tier |
|---|---|---|---|
| Structural Backplate | 316L Stainless Steel | High Chromium-Nickel Stability | Hypoallergenic Skin Contact |
| Strap Fastener | Stainless Steel Tang Buckle | Thread Shear Prevention | High Mechanical Retention |
Table 6 Analysis: The watch uses a 316L steel backplate rather than any precious metals. Because this model contains only this non-precious 316L backplate and steel components, it features no precious metal hallmarks and is accurately described strictly as a high-utility steel analogue timepiece.
7. Operational Power & Current Drain Analysis
| Power Variable | Battery Chemistry | Nominal Voltage | Calculated Cell Lifespan |
|---|---|---|---|
| Energy Cell | Titanium Lithium Ion Cell | 1.5 Volts DC | Permanently Rechargeable Solar |
| Solar Panel | Amorphous Silicon Cell | Regulated Pulse Output | Continuous Clean Conversion |
Table 7 Analysis: The 180-day dark power reserve relies on a high energy-density rechargeable system coupled with an efficient integrated chip. This infrastructure allows for clean, continuous background timekeeping while reserving voltage overhead for the integrated day-date layout.
Official Factory Operation Guide Reference
Figure 1.0: Citizen BM8240-11A Operation Guide.
View Official Factory Manual (Web)
20 Technical FAQs: Engineering & Horological Logic
1. Brand Heritage & Naming Origins
1. What is the history of the Citizen Eco-Drive dress series?
The classic dress series lines date back to Citizen's expansion of the Eco-Drive concept, originally pioneered via solar quartz prototypes in 1976. Since August 2000, H.E. Phillips Ltd has recognized the Eco-Drive movement as a milestone of sustainable consumer horology. Its design philosophy remains focused on low-profile integration, making it a stable asset for any collection.
2. Why is the BM8240-11A model specifically respected?
The BM8240-11A is respected for its integration of a clean white sunray dial configuration alongside a traditional bovine leather band. It represents the quintessential 36mm dress layout. H.E. Phillips Ltd, established in August 2000, has consistently stocked this model because of its unparalleled reliability. It is a watch that bridges the gap between utilitarian tool and classic everyday wear.
3. What does 'Eco-Drive' actually mean for the user?
It is more than a name; it is a technical standard. It refers to the light-powered quartz engine that eliminates the traditional replacement cycles of conventional batteries. This ensures that the watch charges under ambient indoor light or outdoor sun. H.E. Phillips Ltd in Totnes audits every model to ensure these energy retention standards are met.
4. Is Citizen considered a heritage brand in the UK?
Yes, Citizen has been a staple of the British horological landscape since the mid-20th century. Known for their technological breakthroughs in light power, they built a reputation for resilience. H.E. Phillips Ltd, established in August 2000, continues this tradition by offering expert local support in Totnes for this brand.
2. Technical Engineering & Accuracy
5. How accurate is the quartz movement in the BM8240-11A?
The quartz movement in the BM8240-11A is accurate to within ±15 seconds per month. This precision is achieved through a quartz crystal oscillator vibrating at 32,768 Hz. As experts since August 2000, we find this level of accuracy far superior to mechanical watches in this price bracket, providing maintenance-free precision.
6. What is the benefit of the Calibre E101 movement?
The BM8240-11A uses a motor designed to move the hands precisely while drawing minimal energy from its stored solar reserve. This prevents 'hand-drift' and ensures that the second hand aligns with the markers. H.E. Phillips Ltd technical audits confirm that Citizen movements maintain this torque over the entire life of the solar cell.
7. How does the 'Hacking' function work on this model?
Pulling the crown to the second position stops the second hand (hacking). This allows the user to synchronize the watch perfectly with an atomic clock or radio time signal. This is a vital feature for those who require to-the-second accuracy. H.E. Phillips Ltd recommends this practice to all our professional clients in Devon.
8. What is the frequency of the quartz oscillator?
The movement utilizes the industry-standard 32,768 Hz frequency. This specific frequency is used because it is a power of 2 ($2^{15}$), which can be easily divided down to exactly 1 pulse per second by the integrated circuit. This digital division is what provides the incredible reliability Citizen is known for.
3. Materials & Metallurgical Lineage
9. What type of stainless steel is used for the case body?
The outer case of the BM8240-11A is crafted from solid 316L surgical-grade stainless steel, polished under controlled industrial parameters. This high-grade treatment results in a finish that is structurally resilient against traditional daily wear. The manufacturing process provides a brilliant mirror surface that handles environmental vectors.
10. What grade of stainless steel is used for the case back?
The case back is also manufactured from 316L stainless steel, chosen for its corrosion resistance and hypoallergenic properties. Because the case back is the primary contact point with the skin, using 316L ensures that perspiration does not cause tarnishing. We verify that the back is pressure-sealed with a functional gasket protection shield.
11. Is the BM8240-11A suitable as a gift?
Yes, it is one of our most requested gift items. The 36mm case size is considered highly versatile for unisex dress fitment, and the high-contrast dial makes it suitable for users of all ages. H.E. Phillips Ltd has recommended the classic Eco-Drive series for birthdays, retirements, and graduations due to its reputation for reliability.
12. Why is 316L stainless steel used over common metals?
316L stainless steel contains lower carbon levels and added molybdenum, rendering it highly resistant to pitting and localized rust. It acts as an ideal shield for solar watch movements, offering optimal resilience standards while protecting the inner micro-components from mechanical damage.
4. Maintenance & Professional Care
13. How should I clean my Citizen BM8240-11A?
We recommend a gentle wipe with a damp microfibre cloth for the steel case and mineral crystal. For the genuine leather band, keep it free from excess moisture to prevent premature breakdown. Since August 2000, we have advised against using intense abrasive chemical polishes on the external finish to preserve the brilliant polished exterior layer.
14. What is the projected lifestyle lifespan of the solar cell?
The E101 calibre utilizes a rechargeable titanium lithium cell, which provides an exceptional power reserve of up to 20 years or more under continuous daylight cycles. H.E. Phillips Ltd services solar calibres in Totnes. We recommend professional checks to ensure the cell retains its full charging capacity.
15. Does H.E. Phillips Ltd check the gaskets during an audit?
Yes, our horological audit process includes a gasket inspection. The BM8240-11A relies on an O-ring to prevent moisture ingress. As part of our professional service since August 2000, we apply silicone grease to the gasket to ensure it provides a seal, replacing it entirely if compressed.
16. What is the H.E. Phillips Ltd Restoration Audit?
Our Restoration Audit is a multi-point inspection for all stock items. It includes case-lustre restoration, a timing accuracy pulse-test, solar capacitor lux verification, gasket lubrication, and a buckle structural integrity check. Every watch we sell passes this audit before leaving our Totnes workshop.
5. Water Resistance & Environment
17. What is the water resistance rating of the BM8240-11A?
The BM8240-11A is rated at 30 Metres (3 ATM). In horological terms, this means the watch can withstand accidental splashes and rain. It is NOT designed for swimming or showering. H.E. Phillips Ltd technical experts advise keeping the environmental housing evaluated during regular checks to maintain normal seals.
18. Is the Eco-Drive movement resistant to magnetism?
Yes, quartz movements are inherently more resistant to magnetic fields than mechanical watches. However, very strong magnets can temporarily disrupt the stepping motor. Once removed from the field, it will resume normal operation. This model is ideal for electronic-heavy environments.
19. Does the BM8240-11A meet shock resistance standards?
The BM8240-11A is built to standard horological shock resistance specifications. The quartz movement is mounted in a protective spacer that absorbs vibrations. While it is not a specialized ruggedized watch, it is designed to survive the typical activities of professional life easily.
20. How does temperature affect the BM8240-11A?
The quartz crystal is cut to be most accurate at room temperature (approx 25°C). Extreme heat or cold can cause the vibration frequency to shift slightly, leading to small deviations. The BM8240-11A is engineered to perform consistently across standard UK temperature ranges.
© 2026 H.E. Phillips Ltd - Registered Sponsor with the Birmingham Assay Office. All Technical Data verified for accuracy.
Citizen BM8240-11A
Silver Dial Watch
White Dial Watch
Men's Leather Watch
Day Date Watch
36mm Watch
Eco-Drive
Solar Powered
Sustainable Luxury
Splash Resistant
Citizen Totnes
H.E. Phillips Ltd
Luxury Watches 2026
Old Money Aesthetic
Quiet Luxury
No Battery Watch
E101 Movement
South West Jewellers
Classic Mens Watch
Minimalist Design
Authorized Citizen Stockist
East Gate Clock Tower
Royal Seven Stars
River Dart Sustainable.
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