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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsThe G-Shock Mudman GDG-B100 keeps the rugged build the Mudman line is known for and changes the display. Its headline upgrade is a memory-in-pixel (MIP) LCD, which Casio positions as easier to read in direct sunlight, paired with a red LED backlight for use after dark. Casio also adds smartphone connectivity, step tracking, and training functions. The display change is the core of the update; the rest is a broader feature set around it.
What changed on the display
The GDG-B100 uses a MIP LCD in place of the display type used in earlier Mudman models. MIP panels are reflective, so their legibility depends on ambient light rather than on a backlight. Casio says this makes the display readable in direct sunlight, and that is the central claim of the update. The product page puts it in promotional terms: “The MIP LCD delivers outstanding readability, even in direct sunlight.” That is Casio’s own wording, not an independent test result.
![Casio GW-9500-1JF [G-Shock Master of G Series MUDMAN Triple Sensor Model] Watch Japan Import July 2023 Model](https://m.media-amazon.com/images/I/41bbHfxiCdL._SL160_.jpg)
For low light, the watch uses a red LED backlight. Casio presents red as the colour that preserves night vision while still letting the time be read in the dark, which is a reasonable design goal for a field watch, though the product materials do not measure how long the light remains comfortable to read.
As of October 2026, we are not aware of an independent, controlled display comparison between the GDG-B100 and an earlier Mudman. Readers who need a measured answer to “is it easier to read outside?” should look for one before treating the MIP claim as proven. Gear Patrol’s launch coverage, dated October 8, 2026, describes the change as a response to glare-related legibility problems in outdoor use, but it does not publish test figures.
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#1 Best Overall
- Case size (L× W× H): 52 × 46.3 × 16.3 mm
- Shock Resistant, Mud Resistant, 200 meter water resistant, Auto Dual EL Backlights with Afterglow, Low Temperature Resistant, World Time - 29 time zones (48 cities), city code display, daylight saving on/off, 1/100 second stopwatch, Measuring modes: Elapsed time, split time, 1st-2nd place times, 1/100 second stopwatch
- Countdown timer -start time setting range: 1 minute to 24 hours (1-minute increments and 1-hour increments), Auto-repeat, progress beeper, Four Multi-function alarms & 1 snooze alarm, Hourly time signal, Full auto-calendar ,12/24 hour formats, Button operation tone on/off , Flash alert
Features beyond the display
The GDG-B100 is more than a display refresh. Casio lists the following functions on its international product page:
- Timekeeping: world time across 38 cities, four daily alarms, and vibration alerts.
- Timers: a stopwatch and a countdown/interval timer.
- Activity: a step tracker.
- Training: distance, speed, pace, and calorie measurements, with lap memory and an interval timer. The UK product page lists these training measurements.
Smartphone pairing runs through the CASIO WATCHES app. According to Casio’s listing, the app handles automatic time adjustment, watch settings, world time, notifications, and activity logs. It also supports distance correction using the phone’s GPS and a phone finder. Connected functions depend on the phone and app, so the watch’s own features are only part of the picture.
Rank #2
The case is built with bio-based carbon and bio-based resin, and the band is bio-based resin. Casio’s construction claims include shock, dust, and mud resistance and 20 bar water resistance. The UK specification page gives the water rating as 200 metres.
Size, weight, and battery
The UK specification page for the GDG-B100-1A5 gives the following physical figures:
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Rank #3
- Smartphone Link Functions; Battery Level Indicator; New Layer Guard Structure; Tough Solar; Dual Dial World Time; Chronograph
- 200 Meter Water Resistance; Shock Resistance; Neobrite; Bluetooth Capability
- Quartz Movement
- Case Diameter: 53.8mm
- Water resistant 200m (660ft): in general, suitable for professional marine activity and serious surface water sports, but not diving
| Specification | Value (Casio UK listing) |
|---|---|
| Dimensions | 63.6 × 49.6 × 16.2 mm |
| Weight | 66 g |
| Battery | CR2032, approximately two years of life |
| Water resistance | 20 bar; listed as 200 metres |
The battery life is a manufacturer’s approximation under Casio’s stated conditions. It is not a per-user figure, and heavy use of the connected or training functions may shorten it. Check the battery figure against your own use before relying on it.
Models and colourways
Casio’s international page lists three model codes: GDG-B100-1, GDG-B100-1A3, and GDG-B100-1A5. The UK specification page covers the GDG-B100-1A5. Reported colourways are black, green, and mustard/yellow. The sources we checked do not give a full code-to-colour mapping for every market, so confirm the exact code on the retailer’s page before ordering, especially if you want a particular colour.
Rank #4
- Triple Sensor (compass, altimeter/barometer, and thermometer)
- Solar Powered
- Radio- Controlled
- Bluetooth Mobile Link
- Double LED
Price and availability by region
Pricing and release timing vary by market, and the figures below should not be read as a single global price.
| Market | Release timing | Price | Source |
|---|---|---|---|
| Japan | October 2026, as listed by Casio Japan | ¥38,500 including tax (suggested retail price for the listed variant) | Casio Japan, GDG-B100-1A5JF |
| United Kingdom | Listed as new in October 2026 | Not stated on the product page we checked | Casio UK, GDG-B100-1A5 |
| United States | Not yet on sale at Gear Patrol’s publication date | Estimated at about $265 by Gear Patrol, based on overseas listings. This is not a confirmed Casio US price. | Gear Patrol |
Because the US figure is an estimate drawn from overseas listings, treat it as a rough guide until Casio US or an authorised retailer publishes a price. Check the Casio regional site for your market, since availability can differ by country and by colourway.
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- Product ID: 12271060
- Model Number: GW9500-3
- Type: Timepiece
- Engraving: Not Supported
- Band Color: Green
How to decide whether the upgrade matters to you
The GDG-B100 makes most sense if you need a rugged digital watch that is easier to read outdoors and you also want step tracking or structured training data. If your main use is simply telling time in a dim room, the display change may matter less than the price and size. Measure the watch against three questions before buying:
- Do you spend long periods in bright sun or at angles where glare hurts legibility? The MIP display is aimed at this case.
- Will you use the training and smartphone functions? If not, the extra features add little.
- Is 63.6 × 49.6 × 16.2 mm at 66 g comfortable on your wrist? Compare it with the watch you already own, since the case is a large, rugged profile.
We have not examined a retail unit, so comfort, button feel, and real-world sunlight legibility should be checked in person where possible.
The Bottom Line
The GDG-B100’s main change is the MIP LCD, which Casio says is readable in direct sunlight, with a red LED backlight for night use. It adds a broader set of connected and training features, but the display claim rests on manufacturer wording, and pricing outside Japan is either unconfirmed or estimated.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
