Casio Smart Watch. B640WB-1AEF

4.4 4.4 out of 5 stars 4,968 ratings

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From the manufacturer

The CASIO Collection — Beautifully retro

The cult following for the shape, function and colour of the first CASIO digital watch from the 1980s is more up-to-date than ever thanks to the watches in the retro Collection. With warm shades of gold, cool stainless steel and black plastic, these timeless design icons can be combined perfectly with modern style. It's good to know that some things never change.

Display illumination

The watch dial or display illuminates at the touch of a button, helping you to see everything, even in absolute darkness.

Alarm Function

The daily alarm reminds you about recurring events with an acoustic signal at the time you have set.

Waterproof up to 5 bar

Taking a shower or bath with this watch is not a problem. It has been tested for water resistance up to 5 bar/50 metres.

Product specifications

Watch Information
Brand, Seller, or Collection Name Casio
Model number B640WB-1ADF
Part Number B640WB-1ADF
Model Year 2011
Item Shape Square
Dial window material type Mineral
Display Type Digital
Clasp Buckle
Metal stamp 10k
Case material Resin
Case diameter 35 millimeters
Case Thickness 8 millimeters
Band Material Stainless Steel
Band size 10
Band width 20 millimeters
Band Color Black
Dial color Black
Bezel material Kunststoff
Calendar Day-Date-Month
Special features stop watch^countdown^alarm^back light
Item weight 4.23 ounces
Movement Quartz
Water pressure resistance 5 bar
Water resistant depth 50 Meters
Warranty If this product is sold by Amazon, please review the manufacturer’s website for warranty information. If this product is sold by another party, please contact the seller directly for warranty information for this product. You may also be able to find warranty information on the manufacturer’s website.

Product details

  • Is Discontinued By Manufacturer ‏ : ‎ No
  • Product Dimensions ‏ : ‎ 1.53 x 1.38 x 0.37 inches; 4.23 ounces
  • Item model number ‏ : ‎ B640WB-1ADF
  • Department ‏ : ‎ men
  • Batteries ‏ : ‎ 1 Lithium Metal batteries required. (included)
  • Date First Available ‏ : ‎ March 29, 2012
  • Manufacturer ‏ : ‎ CASIO
  • ASIN ‏ : ‎ B007421JGG
  • Customer Reviews:
    4.4 4.4 out of 5 stars 4,967 ratings

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Customer reviews

4.4 out of 5 stars
4.4 out of 5
4,968 global ratings

Customers say

Customers like the quality, appearance and accuracy of the watch. For example, they mention it's a great every day watch, it looks amazing on a 5 inch wrist and that it keeps accurate time. That said, opinions are mixed on fit, backlight, value, and readability.

AI-generated from the text of customer reviews

42 customers mention33 positive9 negative

Customers like the quality of the watch. They say it's a decent watch, awesome, and a great everyday watch. Customers also like the band and case, and mention it'll get lots of compliments.

"It looks good and Casio watches always delivered a long lasting life for me..." Read more

"Very good!" Read more

"I have worn a Casio digital watch for many years. They are durable, inexpensive, and reasonably accurate...." Read more

"...For what it's worth, this is a decent watch if you're outside or in daylight a lot, but since I work indoors most of the time, I found that trying..." Read more

20 customers mention20 positive0 negative

Customers are satisfied with the appearance of the watch. They mention it's good looking, amazing on a 5 inch wrist, and has a simple design. The display is sharp and clear, and it matches with everything.

"It looks good and Casio watches always delivered a long lasting life for me..." Read more

"...The display is sharp and clear, and is much more akin to the classic DW5600 - you get full day and date display..." Read more

"...Otherwise it looks really cool and has all the functions I need like a 24 hour stopwatch, and countdown timer...." Read more

"...This particular Casio digital watch is nicely styled and clearly presents the time, day, and date on an easy to read screen...." Read more

16 customers mention12 positive4 negative

Customers like the accuracy of the watch. For example, they say it's the best for keeping accurate time, it clearly presents the time, day, and date on an easy to read display. That said, they mention that setting up the time was fast and easy. They also appreciate the full day and date display, as well as the countdown timer. Overall, customers are happy with their purchase and recommend it to others.

"...thing: while in timer and stopwatch mode, this watch keeps the time of day displayed; this is something that none of the more expensive G-Shocks do,..." Read more

"...and has all the functions I need like a 24 hour stopwatch, and countdown timer...." Read more

"...bottom button it makes a buzzing sound (see the video) but I cannot set the time...." Read more

"...This particular Casio digital watch is nicely styled and clearly presents the time, day, and date on an easy to read screen...." Read more

14 customers mention5 positive9 negative

Customers are mixed about the fit of the watch. Some mention that it fits great, has a small wrist, and is lite. Others say that it's pretty small for most above-average guys and is very small face watch.

"...Is a little slim, maybe you like that and maybe you dont.I kinda expected more from a 50usd watch, not sure what exactly...." Read more

"...it out for the resin strap from an F91-W (pictured), and it fits perfectly." Read more

"Love it and I use it every day. Only con is the band because it's bulky and it pulls on your wrist hairs sometimes (like once a week)...." Read more

"The watch is small tho compare with one cold" Read more

12 customers mention8 positive4 negative

Customers are mixed about the backlight of the watch. Some mention that it has an awesome full-screen orange backlight that stays for about 2.5 hours. However, others say that the screen is in non-color, the back light is orange, and the display light is grey.

"...form factor is closest to the F91-W, this watch has a great full-screen orange backlight which stays for about 2.5 seconds, unlike those cheaper..." Read more

"...The backlight is orange. Don't think I can return as I scuffed it during the first time wearing it." Read more

"...The switchable back light makes it easy to see in total darkness. It's easy to change the settings...." Read more

"...classier look, true 4-button operation, a countdown timer, an awesome backlight, an alarm that can be set for a specific day, auto calendar, and the..." Read more

10 customers mention4 positive6 negative

Customers are mixed about the value of the watch. Some mention it's very good value for your money, while others say it'll not worth the price.

"...Way too expensive for this watch. It shouldn't cost no more than $15.00 dollars tops." Read more

"I have worn a Casio digital watch for many years. They are durable, inexpensive, and reasonably accurate...." Read more

"This watch is much smaller and more expensive than the compatible ones in Walmart. The band was the only nice thing about it." Read more

"Its a great watch deffinetly worth the price...." Read more

9 customers mention5 positive4 negative

Customers are mixed about the readability of the watch. Some mention that it's very easy to read, presents the time, day, and date on an easy to see screen, while others say that the display is a little difficult to read and the whole screen isn't that clear.

"...is nicely styled and clearly presents the time, day, and date on an easy to read screen...." Read more

"...band is shine, other than that it’s cool and also it kind of hard to read the time." Read more

"...It’s simple and I was looking for something that would be durable, so of course I looked into CasioOverall, a pretty good purchase" Read more

"...Doesn't look like the one advertised, the whole screen isn't that clear....." Read more

4 customers mention0 positive4 negative

Customers are not satisfied with the clasp of the watch. They mention that it's faulty, the strap latch is iffy, and the watch falls off. Some say that the clasp was not secure like their previous watch and that they had to return it.

"...I ordered this watch I was able to wear for a day and then the clasp snapped, and I had to return it. I got a replacement today...." Read more

"I love the watch and totally recommend it EXCEPT that the clasp always comes loose and the watch falls off of my wrist a lot...." Read more

"Great Watch! Strap latch is iffy." Read more

"...The latch was not secure like my previous watch and they will not provide a refund. Do not buy from this 3rd party seller!" Read more

This is the one. Takes the best features from numerous Casios, and none of the cons.
5 Stars
This is the one. Takes the best features from numerous Casios, and none of the cons.
I own a bunch of Casios- the F91-W, the DW290, a few G-Shock squares, and the GW6900; I'd resigned myself to the fact that each one had strengths and weaknesses, and none of them did everything I wanted all at once. So I'm sort of astonished that, upon receiving this watch, it seems to take the best of all of them and combine it into such a great form factor.First: in terms of size, this watch is most akin to the F91-W (see photo for comparison), which I love - it wears light and thin against the wrist, keeping the small size of the 91-W while having a nice rounder side-design.The display is sharp and clear, and is much more akin to the classic DW5600 - you get full day and date display (the F91-W gives only the date and day of the month, not the month itself); also, like the DW5600 and DW290, this has the full basic-module set of functions: alarm, countdown timer, stopwatch (F91-W lacks the timer, which always bugged me). Another thing: while in timer and stopwatch mode, this watch keeps the time of day displayed; this is something that none of the more expensive G-Shocks do, and yet, here it is.Bringing functionality I'd seen only in the DW290, this watch also has the auto-repeat option for the timer - so nice if you're doing things on an interval and don't want to have to keep restarting the alarm. It's a small thing, but it's great to have.Finally, even though the form factor is closest to the F91-W, this watch has a great full-screen orange backlight which stays for about 2.5 seconds, unlike those cheaper models, and the clasp is comfortable and easy to adjust. Just a great watch.Update, one week later: This isn't enough to knock a star off, but the metal bracelet is kind of crappy. I switched it out for the resin strap from an F91-W (pictured), and it fits perfectly.
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Reviewed in the United States on November 14, 2022
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Reviewed in the United States on July 2, 2020
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5.0 out of 5 stars This is the one. Takes the best features from numerous Casios, and none of the cons.
Reviewed in the United States on July 2, 2020
I own a bunch of Casios- the F91-W, the DW290, a few G-Shock squares, and the GW6900; I'd resigned myself to the fact that each one had strengths and weaknesses, and none of them did everything I wanted all at once. So I'm sort of astonished that, upon receiving this watch, it seems to take the best of all of them and combine it into such a great form factor.
First: in terms of size, this watch is most akin to the F91-W (see photo for comparison), which I love - it wears light and thin against the wrist, keeping the small size of the 91-W while having a nice rounder side-design.
The display is sharp and clear, and is much more akin to the classic DW5600 - you get full day and date display (the F91-W gives only the date and day of the month, not the month itself); also, like the DW5600 and DW290, this has the full basic-module set of functions: alarm, countdown timer, stopwatch (F91-W lacks the timer, which always bugged me). Another thing: while in timer and stopwatch mode, this watch keeps the time of day displayed; this is something that none of the more expensive G-Shocks do, and yet, here it is.
Bringing functionality I'd seen only in the DW290, this watch also has the auto-repeat option for the timer - so nice if you're doing things on an interval and don't want to have to keep restarting the alarm. It's a small thing, but it's great to have.
Finally, even though the form factor is closest to the F91-W, this watch has a great full-screen orange backlight which stays for about 2.5 seconds, unlike those cheaper models, and the clasp is comfortable and easy to adjust. Just a great watch.
Update, one week later: This isn't enough to knock a star off, but the metal bracelet is kind of crappy. I switched it out for the resin strap from an F91-W (pictured), and it fits perfectly.
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30 people found this helpful
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Reviewed in the United States on August 13, 2023
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Reviewed in the United States on August 10, 2023
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5.0 out of 5 stars Excelente servicio
Reviewed in the United States on August 10, 2023
Muy buena la calidad y excelente el reloj, muchas gracias
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Top reviews from other countries

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KAMAU KAHIRI
5.0 out of 5 stars Convenient way of keeping your self on time.
Reviewed in Canada on August 28, 2022
Color: BlackVerified Purchase
Abdullah Aldeis
1.0 out of 5 stars Klockan fungerar inte
Reviewed in Sweden on April 21, 2023
Color: BlackVerified Purchase
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Abdullah Aldeis
1.0 out of 5 stars Klockan fungerar inte
Reviewed in Sweden on April 21, 2023
Efter att ha använt den i en dag gick klockan sönder
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Cliente Amazon
5.0 out of 5 stars Bueno bonito y barato.
Reviewed in Spain on March 20, 2023
Color: BlackVerified Purchase
Client d'Amazon
5.0 out of 5 stars Belle montre
Reviewed in France on December 24, 2021
Ben van Houten
5.0 out of 5 stars Nostalgielis, mooi van kleur. Zit perfect.
Reviewed in the Netherlands on August 31, 2021
Color: Black/GreyVerified Purchase
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Ben van Houten
5.0 out of 5 stars Nostalgielis, mooi van kleur. Zit perfect.
Reviewed in the Netherlands on August 31, 2021
Wat een super gave horloge. Mooi vormgegeven. En de kleur is super gaaf. En wat ook mooi is. Dat hij duidelijk leesbaar is. En ook leuk dat hij op ieder uur een biep geeft. En best wel handig een alarm er op. En de horlogeband kun je op de millimeter afstellen. En deze horloge is tijdloos. Dus ik ben helemaal blij met mijn nieuwe aanwinst. En voor de prijs hoef je het zeker niet te laten. Dus dank je wel Amazon. Dit is zeker een van mijn lievelings horloge.
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