Tissot PRX Powermatic 80 vs Casio G-Shock GA-B2100 CasiOak
Tissot's timepiece meets Casio's diver
Quick Verdict
The Casio G-Shock GA-B2100 CasiOak ($100–$150) delivers Casio Quartz (Solar-Powered) technology in the tier below the Tissot PRX Powermatic 80 ($500–$1,000). The G-Shock GA-B2100 CasiOak measures 45.4mm (48.5mm lug-to-lug, 11.9mm thick) and is rated 200m (20 ATM). The PRX Powermatic 80 justifies its premium with Swiss Made heritage and Automatic Powermatic 80.111. Both represent excellent choices in the luxury watch category.
Transparency — We earn a small commission on purchases made through our Amazon links. This doesn't affect our editorial independence.
Specifications Compared
| Feature | Tissot PRX Powermatic 80 | Casio G-Shock GA-B2100 CasiOak |
|---|---|---|
| Price | $500–$1,000 | $100–$150 |
| Case Size | 40mm | 45.4mm (48.5mm lug-to-lug, 11.9mm thick) |
| Movement | Automatic Powermatic 80.111 | Quartz Module 5689 (Tough Solar + Bluetooth) |
| Caliber Type | In-House Automatic (ETA C07.111 base) | Casio Quartz (Solar-Powered) |
| Power Reserve | 80 Hours | About 7 months on a full charge without light; about 18 months in power-saving (Casio) |
| Water Resistance | 100m (10 ATM) | 200m (20 ATM) |
| Crystal | Scratch-resistant Sapphire | Mineral Glass |
| Case Material | 316L Stainless Steel | Carbon Core Guard Resin |
| Origin | Swiss Made | Made in Japan |
Category-by-Category Analysis
Design & Aesthetics
Tissot's design language vs Casio's approach
The Tissot PRX Powermatic 80 features a 316L Stainless Steel case at 40mm with Scratch-resistant Sapphire protection. The Casio G-Shock GA-B2100 CasiOak offers Carbon Core Guard Resin construction at 45.4mm (48.5mm lug-to-lug, 11.9mm thick) with Mineral Glass. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Automatic Powermatic 80.111 vs Quartz Module 5689 (Tough Solar + Bluetooth)
The PRX Powermatic 80 runs the Automatic Powermatic 80.111 (In-House Automatic (ETA C07.111 base), 80 Hours power reserve) at 21,600 vph (3 Hz) frequency. The G-Shock GA-B2100 CasiOak uses the Quartz Module 5689 (Tough Solar + Bluetooth) (Casio Quartz (Solar-Powered), About 7 months on a full charge without light; about 18 months in power-saving (Casio) reserve) at standard. The PRX Powermatic 80 edges ahead on power reserve.
Wearability & Fit
40mm vs 45.4mm (48.5mm lug-to-lug, 11.9mm thick) — different wrist presence
At 40mm, the PRX Powermatic 80 wears more compactly on smaller wrists compared to the G-Shock GA-B2100 CasiOak at 45.4mm (48.5mm lug-to-lug, 11.9mm thick). Water resistance differs: 100m (10 ATM) vs 200m (20 ATM).
Value & Cost of Ownership
Casio sits in the lower tier
The Tissot PRX Powermatic 80 sits at $500–$1,000 and the Casio G-Shock GA-B2100 CasiOak at $100–$150. On the specs that outlast any price: the PRX Powermatic 80 uses Scratch-resistant Sapphire with 80 Hours, against Mineral Glass and About 7 months on a full charge without light; about 18 months in power-saving (Casio) on the G-Shock GA-B2100 CasiOak. Service intervals are typically 5-7 years for both.
Water Resistance
100m (10 ATM) vs 200m (20 ATM)
The PRX Powermatic 80 is rated to 100m (10 ATM) while the G-Shock GA-B2100 CasiOak handles 200m (20 ATM). The G-Shock GA-B2100 CasiOak offers superior water resistance.
Materials Face-Off
| Component | Tissot PRX Powermatic 80 | Casio G-Shock GA-B2100 CasiOak |
|---|---|---|
| Case alloy | Stainless steel 316L (medical-grade, with composition Cr 16–18%, Ni 10–14%, Mo 2–3%) — the standard mid-range Swiss spec; not 904L (Rolex Oystersteel | Casio's proprietary monocoque case technology integrating carbon fibers into fine resin. The carbon fibers dramatically raise the tensile strength and modulus of elasticity of the case structure, allowing the GA-2100 to achieve an 11.8mm thickness — the thinnest analog G-Shock at launch — while maintaining full 10m drop impact resistance. Total case weight: 51g. |
| Sapphire crystal | Synthetic corundum (Al₂O₃) grown via the Verneuil process, Mohs hardness 9. Anti-reflective coating on the interior surface only (single-side AR is st Mohs 9 | Flat mineral glass with Mohs hardness ~6. Thermally tempered for impact resistance — flexes under force rather than shattering like sapphire. Not scratch-proof, but replacement crystals cost ~$10. |
| Lume specification | Super-LumiNova on the hands and markers. Grade and glow duration are not published by the manufacturer for this reference, so neither is claimed here. | Durable urethane polymer resistant to sweat, saltwater, UV radiation, and skin oils. Features quick-release spring bars. Known to last 5–10 years with daily wear before degradation. |
| Bracelet alloy | Stainless steel 316L matching the case. | Secured by 4 Phillips screws for 200m (20 ATM) water resistance. The GA-B2100 is Tough Solar: a rechargeable cell topped up by any light, so there is no coin cell to swap. Casio rates a full charge at about seven months of normal use without light, and about eighteen months in power-saving. |
| Premium Lineage: Cobarion® & DAT55G Titanium (MRG-B2100) | — | The luxury MRG-B2100 variant ($3,500+), hand-assembled at Yamagata Casio's Premium Production Line (PPL) by certified "Medalist" craftsmen, uses Cobarion® (cobalt-chromium alloy, 4× harder than pure titanium) bezels and DAT55G titanium (3× harder than pure titanium) bracelet links. |
Cost of Ownership Compared
Who Should Pick Which
Pick the Tissot PRX Powermatic 80 if…
- Strong value proposition under $1,000 with automatic Swiss movement
- Active lifestyle wearers — 100m water resistance handles swimming and water sports
- Weekend warriors — 80-hour power reserve means it survives two days off the wrist
- Those who prioritize scratch resistance — sapphire crystal
- Integrated-bracelet aesthetic fans wanting the Royal Oak look for 1/20th the price
Pick the Casio G-Shock GA-B2100 CasiOak if…
- Anyone wanting an indestructible daily beater under $100 with serious design credibility
- Water sports enthusiasts — 200m WR with G-Shock shockproofing
- Watch modding enthusiasts — massive aftermarket ecosystem of metal conversion kits
- High-end collectors needing a dedicated beater alongside their luxury pieces
Tissot PRX Powermatic 80
- Retail markup is generous. The PRX commonly transacts at 30–40% under retail on Jomashop, Tissot's own e-commerce promotions, and authorized online dealers. Paying full $725 retail is rarely the right move — it usually means immediate ~30% loss the moment you walk out the door.
- Proprietary endlink limits strap options. The integrated bracelet design means you cannot easily put a NATO, leather two-piece, or rubber strap on the PRX without specialist hardware. This bothers some buyers more than they expect.
- Bracelet sizing is fiddly. Links are joined by screws (good — adjustable at home with a tool), but the screws are tiny and stripping them is common for inexperienced owners. Take it to a watchmaker for sizing if you're unsure.
- 3 Hz "slow" seconds. The reduced frequency (21,600 vph vs. 28,800 vph in some peer movements) means the seconds hand visibly sweeps at 6 ticks/second rather than 8. Some buyers expecting the smoother high-beat sweep find this a minor disappointment.
Casio G-Shock GA-B2100 CasiOak
- Stealth-black legibility deficit: The GA2100-1A1 has absolutely no Neobrite luminescent paint on hands or indices. Low-light readability is poor — you must rely entirely on the Double LED Super Illuminator.
- Mineral glass scratches: Not sapphire. Daily beater use will accumulate minor scuffs over time. Replacement crystals are cheap (~$10) but require caseback removal.
- Tiny digital subdisplay: The LCD window at 4:30 is small and genuinely difficult to read for anyone with less than perfect vision. The Hand-Shift feature (sweeps hands to 7:35 position to clear the LCD) helps but isn't a substitute for a full digital display.
- Module 5689 is quartz: For mechanical-watch purists, this is a non-starter. For everyone else, it's a feature — better accuracy (±15 sec/month), no winding, no expensive servicing, and solar charging that never needs a battery change.
Our Verdict
Tissot
PRX Powermatic 80
Choose the Tissot PRX Powermatic 80 if you prioritize In-House Automatic (ETA C07.111 base) engineering, Swiss Made craftsmanship, and 100m (10 ATM) water resistance. At $500–$1,000, it delivers Automatic Powermatic 80.111 with 80 Hours power reserve.
Check Price on AmazonCasio
G-Shock GA-B2100 CasiOak
Choose the Casio G-Shock GA-B2100 CasiOak if you value Casio Quartz (Solar-Powered) technology, Made in Japan heritage, and 45.4mm (48.5mm lug-to-lug, 11.9mm thick) proportions. At $100–$150, the Quartz Module 5689 (Tough Solar + Bluetooth) with About 7 months on a full charge without light; about 18 months in power-saving (Casio) power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Tissot PRX Powermatic 80 and Casio G-Shock GA-B2100 CasiOak represent two distinct approaches to fine watchmaking — the Tissot bringing Swiss Made tradition while Casio delivers Made in Japan engineering.
Frequently Asked Questions
More Comparisons
Explore These Watches
How This Page Was Made
Our comparisons are generated from a hand-maintained specification database and reviewed under our editorial standards. We use AI tools to assemble pages from that data. We don’t invent specs: every number traces back to the database, and when we correct an entry, the fix is applied site-wide. As an Amazon Associate, The Horologist earns from qualifying purchases.