The Casio G-Shock GA-100-1A4 is a large analog-digital watch with a broad set of timing functions, world time, shock resistance and a manufacturer-rated 200-metre water resistance. Its 55 mm case length and 51.2 mm width make its size the main buying consideration: it is best suited to someone who actively wants a substantial watch, not a compact everyday design. Casio’s official listing identifies the model as GA-100-1A4; “X-Large Combi” is not established there as an official model name.
How big is the GA-100?
Casio lists the GA-100-1A4 at 55 × 51.2 × 16.9 mm (length × width × height) and 70 g. Those dimensions describe a notably broad, thick case, so check them against a watch you already own or measure your wrist before buying. The figures are manufacturer specifications, not a guarantee of how the watch will sit on an individual wrist. Casio lists a compatible band sizing range of 145 to 215 mm; that range does not confirm compatibility for any particular replacement strap.
The case and band are resin, and the crystal is mineral glass. Casio also specifies shock-resistant and magnetic-resistant construction. These are the manufacturer’s stated materials and ratings, not results from independent testing.
What does the analog-digital display show?
The GA-100 combines an analog center dial with digital displays on either side. Casio describes it this way: “The popular G-SHOCK three-dial face design incorporates one analog dial in the center, with digital dials on either side.” The arrangement presents analog and digital timekeeping together, alongside the watch’s other functions. Casio also notes raised hour markers and oversized buttons with a checkered anti-slip surface.
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- EXTRA LARGE DIGITAL DISPLAY FOR MAXIMUM READABILITY The Casio AE-1500WH-5AVCF features an oversized wide-face display designed for quick, easy viewing of time, date, and functions at a glance. The large digital screen makes it ideal for outdoor adventures, travel, work, fitness, and everyday wear.
- RUGGED KHAKI DESIGN BUILT FOR OUTDOOR ADVENTURES Featuring a military-inspired khaki resin band, durable resin case, and resin glass crystal, this Casio digital watch delivers a rugged look with lightweight comfort. The 100-meter water resistance makes it suitable for swimming, outdoor activities, and daily wear.
- 10-YEAR BATTERY LIFE POWERED BY CR2032 LITHIUM BATTERY Powered by a CR2032 lithium battery, the AE-1500WH-5AVCF delivers approximately 10 years of battery life, providing dependable long-term performance while minimizing battery replacements.
- ADVANCED DIGITAL FUNCTIONS FOR TRAVEL, TRAINING & EVERYDAY USE Stay organized with Dual Time, a 1/100-second stopwatch, and a 24-hour countdown timer with auto-repeat. Additional features include 5 multi-function alarms with snooze, hourly time signal, and selectable 12/24-hour format.
- AMBER LED BACKLIGHT & LONG-LASTING CASIO RELIABILITY The built-in amber LED backlight with afterglow provides clear visibility in low-light conditions. Additional features include a full auto calendar through 2099 and quartz accuracy of approximately ±30 seconds per month for dependable everyday timekeeping.
The product page does not establish how easy the displays are to read in every lighting condition or how convenient the controls are in use. The watch has an amber LED light, but the specification alone cannot settle whether the layout will suit your eyesight or preferences.
Which functions does the GA-100 include?
Casio’s specification list gives the GA-100-1A4 a feature set that goes beyond basic timekeeping:
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- 【Carbon Fiber Ultra-Lightweight Digital Watch】Constructed from advanced reinforced carbon fiber composite, this ultra-lightweight unisex digital watch offers exceptional durability and all-day comfort, weighing only 43g for a barely-there feel on the wrist without sacrificing strength or style.
- 【Watch with Upgraded Backlight for Men/Women】Equipped with an enhanced LED backlight, providing brilliant screen illumination for effortless reading of the time—whether you’re outdoors in the sun or in low-light environments.
- 【Breathable Nylon Strap】Featuring a 24mm/0.94in wide band crafted from elastic knitted nylon, this strap weighs a mere 5g for a feather-light, barely-there feel. The breathable material and secure velcro closure provide a customizable, comfortable fit for all-day wear and any sports challenge.
- 【Multifunctional Military Watch】This men's wrist watch is a multi-functional outdoor sports watch with dual time,alarm,calendar,countdown,stopwatch,EL backlight and other functions.It can meet almost all the needs of military watches.It’s a great companion for swimming, climbing, cycling, fishing, adventure and etc.
- 【5ATM Waterproof Watch for Active Lifestyles】With 50M (164 Ft) water resistance, this watch is built to handle swimming, intense workouts, and daily activities worry-free. For lasting performance: Please rinse after contact with saltwater or sweat, avoid pressing buttons underwater, and do not expose to hot water.
- World time: 29 time zones, covering 48 cities plus Coordinated Universal Time (UTC).
- Stopwatch: measures to 1/1000 of a second.
- Speed indication: a velocity indicator is listed among the watch’s functions.
- Countdown timer: a maximum range of 24 hours.
- Alarms: five daily alarms, including one snooze alarm.
- Calendar: full auto-calendar through 2099.
- Accuracy: stated by Casio as ±15 seconds per month.
These are listed capabilities; they do not indicate that the stopwatch or speed function is a substitute for dedicated measurement equipment.
How should you interpret its water resistance and battery life?
Casio rates the GA-100-1A4 for 200-metre water resistance. This is the manufacturer’s rating; the product page does not establish a particular diving certification. Follow Casio’s care guidance for use and maintenance rather than treating a water-resistance rating as a promise that the watch will remain sealed indefinitely.
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Rank #3
- EXTRA LARGE DISPLAY DESIGNED FOR QUICK, EASY READING The Casio AE-1500WH-8BV features an oversized wide-face digital display that makes checking the time, date, and functions easy at a glance. The large screen design is ideal for outdoor activities, work environments, fitness, travel, and everyday wear.
- RUGGED BLACK DESIGN WITH 100M WATER RESISTANCE Built for active lifestyles, this Casio digital watch features a durable resin case, resin glass crystal, and comfortable resin band. The 100-meter water resistance provides dependable performance for swimming, outdoor adventures, rain, and daily use.
- 10-YEAR BATTERY LIFE POWERED BY CR2032 LITHIUM BATTERY Powered by a CR2032 lithium battery, the AE-1500WH-8BV delivers approximately 10 years of battery life, helping reduce maintenance while providing long-lasting reliability.
- ADVANCED DIGITAL FEATURES FOR SPORTS, TRAVEL & EVERYDAY USE Stay prepared with Dual Time, a 1/100-second stopwatch, and a 24-hour countdown timer with auto-repeat. Additional functions include 5 multi-function alarms with 1 snooze alarm, hourly time signal, and selectable 12/24-hour time format.
- AMBER LED BACKLIGHT WITH AFTERGLOW FOR NIGHTTIME VISIBILITY The built-in amber LED backlight with afterglow makes the display easy to read in low-light conditions. Additional features include a full auto calendar through 2099 and quartz accuracy of approximately ±30 seconds per month for dependable everyday timekeeping.
Casio gives an approximate battery life of two years on a CR1220 battery. “Approximate” matters: this is not a guaranteed replacement interval, and actual life can vary with use. The cited specifications do not provide a replacement cost or say that owners should carry out the replacement themselves. Casio’s India support page lists battery replacement, band, use and care, troubleshooting, and after-sales service categories, but does not establish local prices or service turnaround. See Casio’s GA-100-1A4 support page for those support categories.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Is the Casio G-Shock GA-100 worth buying?
The documented case dimensions and functions point to a clear kind of buyer: someone who wants a large analog-digital G-Shock and values world time, a fine-resolution stopwatch, a long-range countdown timer and multiple alarms. The trade-off is equally clear: if you prefer a smaller, thinner watch, the 55 × 51.2 × 16.9 mm case is a substantial commitment. This is a specification-led assessment; the available manufacturer information does not support claims about real-world comfort, legibility, durability in use or independent performance.
Rank #4
- Bold Field Design: Green 41mm case with digital dial pairs with an adjustable black strap fitting wrists up to 8 inches for daily wear
- Serious Performance: A 100-hour chronograph tracks lap and split times, plus a 24-hour countdown timer and a month, day and date calendar for everyday training
- Everyday Alarms: Three daily, weekday, or weekend alarms with a 5-minute backup, 24-hour military time mode, and two time zones keep you on schedule
- Night-Ready Visibility: An acrylic lens and INDIGLO light-up dial keep the gray digital display easy to read from dawn to dusk and after dark
- Built to Last: A Timex watch is designed for durability and everyday reliability; every piece reflects our commitment to quality without compromise
Casio’s official GA-100-1A4 product page has the full specification list. Regional pricing, availability, warranty and support can differ, so check the terms for the market where you plan to buy.
Quick Recap
Best Value
- Digital Watch with Multi-Functional: shock resistant, water resistant, stopwatch, night light, auto date, calendar, alarm, 12/24H, hourly signal
- Perfect for All Sports: shockproof with large face and super easy to read LED screen, ideal for running, swimming, hiking, fishing and other outdoor and indoor sports
- Waterproof with Stylish Minimalism: 164 Ft / 50M water resistant with unique simple military black dial. Shower, swimming, raining, sweating, no problem!
- Build for Comfort & Durable: soft imported PU band and long last stainless steel back case, a great value you don't want to miss
- Waterproof: 164 Ft / 50 M water resist, Please DONOT press any buttons underwater, and in case of damaging waterproof ring,please keep it away from steam and hot water.
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