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One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchThe Grand Seiko SBGM245 and SBGM247 are stainless-steel mechanical GMT watches built around the same 9S66 movement and case. The practical choice is chiefly the dial: blue on the SBGM245, green on the SBGM247. Both offer a second-time-zone display, a locally adjustable hour hand, a 40.5 mm case and a manufacturer-rated 20 bar water resistance.
SBGM245 vs. SBGM247 at a glance
| Specification | SBGM245 | SBGM247 |
|---|---|---|
| Dial | Blue | Green |
| Case dimensions | 40.5 mm diameter × 48.6 mm lug-to-lug × 14.4 mm thick | 40.5 mm diameter × 48.6 mm lug-to-lug × 14.4 mm thick |
| Band width | 20 mm | 20 mm |
| Movement | Caliber 9S66, automatic with manual winding | Caliber 9S66, automatic with manual winding |
| Power reserve | Approximately 72 hours | Approximately 72 hours |
| Water resistance | 20 bar | 20 bar |
| Light and crown features | LumiBrite on hands and indexes; screw-lock crown | LumiBrite on hands and indexes; screw-down crown |
Specifications are from Grand Seiko’s SBGM245 listing and SBGM247 listing. The dimensions are identical, so wrist fit is not a meaningful distinction between the two references on paper. Consider the full 48.6 mm lug-to-lug length and 14.4 mm thickness, not just the 40.5 mm diameter, when assessing how the case may sit on your wrist.
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What actually differs: blue versus green
SBGM245: blue dial
The SBGM245 is the blue-dial version. Grand Seiko’s Japanese boutique describes its color as ocean-like. That is brand language rather than a measurable color comparison, but it conveys the intended character of this option.
SBGM247: green dial
The SBGM247 has a green dial, which Grand Seiko characterizes as wilderness-inspired. If green is the color you want on the wrist, that is the straightforward reason to choose the SBGM247; the underlying listed case and movement specifications match the SBGM245.
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- See-through case back
- Date display
- Screw-down crown
- 40mm Diameter
- Weight 178.0 g
How the 9S66 GMT works
Both watches use Grand Seiko’s mechanical 9S66 caliber, which supports automatic winding and manual winding. The GMT hand displays a second time zone on a 24-hour scale, while the local hour hand can be adjusted independently. Grand Seiko says the hour hand can be adjusted without compromising accuracy and lists a calendar-linked time-difference adjustment function on both model pages.
That arrangement is useful when changing local time while traveling: the hour hand can move to the new local hour while the GMT hand continues to indicate the other time zone. The calendar-linked adjustment is part of the listed function set; consult the operating instructions for the exact setting sequence.
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- Three-fold clasp with push button release
- Dual-curved sapphire crystal
- Power reserve display on the back
- Power resrve Approx. 72 hours(3 days)
Accuracy and power reserve
Grand Seiko lists an approximately 72-hour power reserve for each watch. Its specifications also distinguish two accuracy figures: a mean daily rate of +5 to −3 seconds per day, measured on the uncased movement in six positions under controlled conditions, and normal-use accuracy of +10 to −1 seconds per day. The controlled mean-rate figure is not a promise of the same result on a wearer’s wrist; the normal-use figure is the more relevant manufacturer specification for everyday wear.
Water resistance and everyday features
Grand Seiko specifies 20 bar water resistance for both references and lists LumiBrite on the hands and indexes. The crown terminology differs slightly between the listings: the SBGM245 page says “screw-lock crown,” while the SBGM247 page says “screw-down crown.” These are manufacturer-listed specifications, not an independent assessment of either watch’s performance in water.
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- 24-hour hand (dual time display function)
- Power Reserve Approx. 55 hours
- See-through case back
Price context
Grand Seiko’s US price-adjustment notice set the price of each model at USD 5,800 before tax, effective November 1, 2024; the notice listed USD 5,700 through October 31, 2024. This is a dated US MSRP, not a current quote or a price for other regions. Check the current price with Grand Seiko or a local authorized retailer. Grand Seiko’s US price adjustment notice.
Which one should you choose?
- Choose the SBGM245 if you prefer the blue dial.
- Choose the SBGM247 if you prefer the green dial.
- Compare the case on your wrist using all three dimensions—40.5 mm across, 48.6 mm lug-to-lug and 14.4 mm thick—rather than judging by diameter alone.
Time+Tide Watches published a video titled “HANDS ON: Grand Seiko’s tool-tastic steel bezel GMTs” on November 23, 2021, and its description names both models. That establishes the existence and subject of the video, but does not substantiate specific wearing impressions here. Watch the Time+Tide video.
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.
