Description
SEIKO PROSPEX Alpinist SBDC091 Automatic Men’s Watch
The SEIKO PROSPEX SBDC091 is a modern Alpinist that combines an unmistakable green dial with gold-colored details and a brown calf-leather strap. Developed for outdoor recreation and everyday use, it brings together a compact stainless-steel case, an internal rotating compass ring and the approximately 70-hour power reserve of Caliber 6R35.
SBDC091 is the Japanese domestic reference distributed through SEIKO Global Brand Core Shops. Its corresponding international reference is SPB121J1, commonly marketed as SPB121.
Key Highlights
- Classic Alpinist design with a green dial and gold-colored accents
- Mechanical Caliber 6R35 with automatic and manual winding
- Approximately 70-hour power reserve when fully wound
- Internal rotating ring with an approximate compass scale
- Lens-equipped sapphire crystal with inner anti-reflective coating
- Compact 39.5 mm stainless-steel case
- Brown calf-leather strap with a push-button folding clasp
- See-through screw case back
- 20-bar enhanced water resistance for daily use
- Made in Japan
A Modern Interpretation of the Alpinist
The Alpinist traces its roots to the Laurel Alpinist introduced in 1959 as Seiko’s first watch designed for sports and outdoor activities. The SBDC091 preserves that adventurous character through its distinctive dial, practical compass ring and robust construction while remaining compact enough for everyday wear.
The deep green dial changes character with the surrounding light and is complemented by gold-colored hands, applied markers and dial details. A date display at three o’clock is enlarged by a lens integrated into the sapphire crystal.
Mechanical Caliber 6R35
The watch is powered by SEIKO Caliber 6R35, a mechanical movement with automatic winding and a manual-winding mechanism. When fully wound, it provides an approximately 70-hour power reserve.
Caliber 6R35 operates at 21,600 vibrations per hour, uses 24 jewels and includes a date display and stop-seconds function. Its stated accuracy is +25 to −15 seconds per day when worn on the wrist within the specified temperature range.
Internal Compass Ring
An internal rotating ring with an approximate compass scale reinforces the Alpinist’s outdoor identity. The ring is operated by the additional crown positioned near four o’clock and can be used with the position of the sun to estimate direction in the Northern Hemisphere.
The compass ring is intended as an approximate directional aid rather than a substitute for dedicated navigation equipment.
Sapphire Crystal and Outdoor-Ready Construction
The stainless-steel case measures 39.5 mm in diameter, 46.4 mm from lug to lug and 13.2 mm in thickness. It is fitted with a lens-equipped sapphire crystal featuring an anti-reflective coating on its inner surface.
A screw-down crown and screw case back contribute to 20-bar enhanced water resistance for daily use. LumiBrite on the hands and hour markers supports visibility in dark conditions, while magnetic resistance provides additional practicality for daily wear.
Brown Calf-Leather Strap
The green and gold dial is paired with a brown calf-leather strap that complements the watch’s classic outdoor styling. A push-button three-fold clasp provides a secure fit while retaining the appearance of a traditional leather strap.
The see-through case back incorporates Hardlex glass, allowing the mechanical movement to be viewed while the watch is off the wrist.
Product Specifications
| Brand | SEIKO |
|---|---|
| Collection | PROSPEX Alpinist |
| Domestic Reference | SBDC091 |
| International Reference | SPB121J1, commonly marketed as SPB121 |
| Distribution | SEIKO Global Brand Core Shop exclusive model in Japan |
| Edition | Regular model; not a limited edition |
| Display | Analog |
| Dial Color | Green with gold-colored accents |
| Movement | Mechanical automatic with manual winding |
| Caliber | 6R35 |
| Movement Frequency | 21,600 vibrations per hour (6 beats per second) |
| Accuracy | +25 to −15 seconds per day when worn on the wrist at 5°C to 35°C |
| Power Reserve | Approximately 70 hours when fully wound |
| Jewels | 24 |
| Movement Functions | Date display and stop-seconds function |
| Case Material | Stainless steel |
| Case Diameter | 39.5 mm |
| Lug-to-Lug Length | 46.4 mm |
| Case Thickness | 13.2 mm |
| Crystal | Sapphire crystal with date magnifier |
| Crystal Coating | Anti-reflective coating on the inner surface |
| Compass | Internal rotating ring with approximate compass scale |
| Main Crown | Screw-down crown |
| Case Back | See-through screw case back with Hardlex glass |
| Luminous Material | LumiBrite on hands and indexes |
| Strap Material | Brown calf leather |
| Lug Width | 20 mm |
| Clasp | Push-button three-fold clasp |
| Water Resistance | 20-bar enhanced water resistance for daily use |
| Magnetic Resistance | 4,800 A/m |
| Weight | Approximately 87 g |
| Release Date | January 11, 2020 |
| Country of Manufacture | Japan |
| JAN Code | 4954628453532 |