
Tap the image to enlarge

Citizen BM7170-53L Titanium Eco-Drive Bracelet Watch - W3711
Ref. BM7431-51L
Sits in Citizen’s upper tier here — more premium than three quarters of the Citizen watches we list, which start at £139.
Price range £139 to £1,145 across 90 Citizen watches in stock.Super Titanium is Citizen's own alloy, hardened to roughly five times the resistance of standard titanium — meaning a 43mm bracelet watch that weighs under 100 grams and will not show the surface marks that accumulate on steel over years of daily wear. At that size and weight together, it sits on the wrist with very little presence in the physical sense, which is an unusual combination for something this wide. The Eco-Drive E111 stores enough charge to run for six months in complete darkness, so the solar cell is genuinely a set-and-forget proposition rather than a theoretical one. The blue dial reads clearly at an angle under office light and rather well in low conditions given the luminous markers, without making any particular drama of either.
- Reference
- BM7431-51L
- Brand
- Citizen
- Case size
- 45mm
- Case material
- Titanium
- Case shape
- Round
- Dial
- Blue
- Crystal
- Sapphire
- Movement
- Solar
- Calibre
- E111
- Functions
- Date
- Water resistance
- 100m
- Bracelet / strap
- Titanium bracelet
- Strap colour
- Silver
- Clasp
- Folding clasp
- Lume
- Luminous
- Retailer
- F.Hinds
Learn more about Citizen
The Shokosha Watch Research Institute began in Tokyo in 1918, and the Citizen name was given to its first pocket watch in 1924 by the then mayor of Tokyo, Shinpei Goto, who wanted a watch that would be available to ordinary citizens rather than only the wealthy. The company formally took the name in 1930.
That founding intention has held. Citizen is the largest watch manufacturer in the world by volume and is fully vertically integrated, making its own movements, cases, and electronic components.
Its most significant technology is Eco-Drive, introduced in 1976 and refined over decades. A photovoltaic cell beneath the dial converts any light — including indoor light — into stored energy, so the watch never needs a battery change. Citizen has sold well over a hundred million Eco-Drive watches, and the environmental argument is substantial: hundreds of millions of cells not discarded.
The company also produced the first analogue quartz watch with a titanium case in 1970, the first professional dive watch with an electronic depth sensor, and the Caliber 0100, an Eco-Drive movement accurate to within one second a year — the most accurate independent watch movement ever put into production.
Citizen owns Bulova, Frederique Constant, Alpina, and the movement manufacturer Miyota, whose calibres power a large share of the affordable mechanical watch market worldwide.
- 1918
- The Shokosha Watch Research Institute is founded.
- 1924
- The Citizen name is given to its first pocket watch.
- 1976
- Eco-Drive light-powered technology is introduced.
- 2018
- The Caliber 0100 achieves accuracy of one second a year.
Also in 5 collections
This watch appears in Back in Stock (2,765), Watches 44mm and Over (1,013), Blue Dial Watches (928), Solar & Kinetic Watches (228) and Titanium Watches (174).
Manufacturer’s guarantee
What the specifications mean
Strengths
- 100m water resistance covers swimming and watersports
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
- One of Citizen's more premium watches
Worth knowing
- 45mm is a large watch with real presence
Citizen BM7170-53L Titanium Eco-Drive Bracelet alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | BM7431-51L | 010-02934-00 | MTRH2S602 |
|---|---|---|---|
| Price | £329 | £299 | £320 |
| Case size | 45mm | 45mm | 44mm |
| Water resistance | 100m | 100m | 100m |
| Movement | Solar | Solar | Solar |
| Strap | Titanium bracelet | Silicone strap | Stainless steel bracelet |
| This watch | Closely matched | Closely matched |
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 100m it is rated for swimming and snorkelling, though not for diving.
Will the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Does it need a battery?
No. It charges from light, and the cell behind that is designed to last a decade or more.
Is it a men's or women's watch?
Listed as men's.
Cheapest place to buy
F.Hinds is the only UK retailer we track stocking this reference new, at £329. There is nothing to compare it against today.
Who are F.Hinds?
F.Hinds has been run by the same family since 1856 and is now in its fifth generation, with more than 115 shops across England and Wales. They are a member of the Responsible Jewellery Council and an Authorised Diamond Dealer.
More Citizen watches like the BM7170-53L Titanium Eco-Drive Bracelet
In stock, and close on style and price






