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Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →The Seiko Astron GPS Solar SSH101J1 and SSH105J1 are two versions of Seiko’s 2021 Astron GPS Solar Limited Edition. Each was limited to 800 pieces. Their practical appeal is the same: GPS-assisted time-zone adjustment, solar charging, dual-time display, and a lightweight titanium case and bracelet. Seiko’s official material presents them as a pair with shared core specifications; it does not establish a technical difference between the references.
What the SSH101J1 and SSH105J1 have in common
Seiko lists both references under its Astron GPS Solar 2021 Limited Edition. Each model is limited to 800 pieces, and the company describes the design as a gradation-colored dial inspired by Tokyo at night. The official product page specifies Lumibrite on the hands and indexes for visibility in low light. Seiko’s 2021 limited-edition product page is the source for the model and edition details.
- Movement: Caliber 5X53 GPS Solar Dual-Time.
- Case and bracelet: Titanium with super-hard coating. Seiko says the titanium is 40% lighter than steel; this is the manufacturer’s product specification, not an independent comparative test.
- Water resistance: 20 bar, as specified by Seiko.
- Included strap: An additional silicone strap, described by Seiko as easy to fit.
- Edition size: 800 pieces for each reference.
How GPS Solar time adjustment works
The 5X53 movement uses GPS signals to adjust time and time zone. Seiko says it can connect to GPS up to twice a day to maintain precision, and that it adjusts automatically for daylight saving time. A button-operated time-zone change is also available, so a traveler can request a zone adjustment rather than wait for an automatic connection. The watch supports dual time and lets the wearer switch the primary display between home and local time.
Solar charging supplies power to the movement. That removes the need for routine battery replacement, but it does not mean the watch never needs light or attention: follow Seiko’s instructions for charging and operation, particularly if the watch has been stored or its power reserve is low.
#1 Best Overall
- STUNNING BLUE DIAL: this automatic men's watch features a deep blue, pressed pattern and gloss finish surrounded by a stainless steel watch case
- AUTOMATIC: these self-winding, automatic men's watches are powered by your movement, with a power reserve of 41 hours
- STAINLESS STEEL: features a durable stainless steel watch case and bracelet with see through caseback
- WATER-RESISTANT: these men's wrist watches are water-resistant down to 50 meters
- 4R35 CALIBER: equipped with the reliable caliber 4R35 automatic movement, this accurate men's watch keeps precise time
In a 13 April 2022 press release discussing other 5X53 models, Seiko also described caliber-level functions including world time across 39 time zones, a perpetual calendar to February 2100, dual time with AM/PM indication, and stated accuracy of ±15 seconds per month without GPS reception at 5–35°C. These are Seiko’s published claims in that broader caliber and other-model context, not a separate test result for the SSH101J1 or SSH105J1. Read Seiko’s 13 April 2022 5X53 press release.
How to tell the two references apart
The official material establishes the references as a limited-edition pair, but does not document a movement, case, or functional difference between SSH101 and SSH105. Any distinction a buyer can confirm should therefore be based on the specific watch’s dial and other visible design details in reliable product imagery, rather than an assumed difference in performance.
Rank #2
- CLASSIC FIELD WATCH DESIGN: Clean white dial with bold Arabic numerals and a compass bezel for excellent readability and everyday outdoor style.
- AUTOMATIC MECHANICAL MOVEMENT: Reliable Seiko automatic movement with a 41-hour power reserve delivers smooth, battery-free performance.
- DURABLE STAINLESS STEEL BUILD: Constructed with a stainless steel case and solid link bracelet, featuring a Hardlex crystal and see-through case back.
- DAY-DATE DISPLAY: Easy-to-read day and date window with luminous hands and markers for quick timekeeping in various lighting conditions.
- EVERYDAY COMFORT: Designed for work, travel, hiking, and casual wear with 100M water resistance and a secure deployment clasp.
When comparing listings, check photographs against the exact reference printed in the listing and on the watch. Then compare condition, included accessories, seller provenance, warranty, regional variant, and asking price. The fact that both are limited editions does not by itself establish present-day scarcity, resale value, or investment potential.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Availability and strap compatibility
At launch, Seiko said the models would be available through Seiko Boutiques and selected Seiko retailers worldwide. That launch statement does not confirm current stock. Check current, region-specific sellers for availability and price; neither is established by the official product material cited here.
Rank #3
- BLUE DIAL: this handsome men’s watch features a striking deep blue dial with luminous dial indicator hands and markers and date calendar to keep you organized
- BLUE & BLACK BEZEL: with a 24-hour bezel and easy-to-read fourth hand, this GMT watch helps you keep time as you travel
- DURABLE UTILITY: these versatile men’s wrist watches feature a 42.5mm stainless steel watch case and bracelet, for a classic, timeless look.
- WATER-RESISTANT: this rugged sports watch is water-resistant up to 100 meters
- 4R34 CALIBER: equipped with the reliable 4R34 caliber, these automatic watches for men ensure the most accurate in self winding timekeeping, with 41 hours of reserve power and manual winding option
Seiko says each watch includes an additional silicone strap, but this does not establish that a generic replacement strap will fit. Before buying an aftermarket strap, confirm compatibility with the exact reference and attachment dimensions. The cited product information does not verify third-party strap fit.
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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.
