Description
SEIKO PROSPEX Diver Scuba SUMO SBDC177
The SEIKO PROSPEX SBDC177 is a Japanese Domestic Market mechanical diver’s watch from the Diver Scuba collection. Commonly known among enthusiasts as the “SUMO,” this Core Shop model combines its substantial signature case with a gray-tone gradient dial inspired by the ocean reflecting the first light of dawn.
Ocean-Inspired Gray Gradient Dial
The textured gray-tone dial uses a graduated color treatment to evoke the changing appearance of the sea at dawn. Large hands and indexes provide a strong, functional display, while LumiBrite applied to the hands, indexes and bezel supports visibility in dark conditions. A date window adds a practical calendar function.
Automatic Caliber 6R35
The SBDC177 is powered by SEIKO’s Caliber 6R35, a mechanical automatic movement that can also be wound manually. It operates at 21,600 vibrations per hour, uses 24 jewels and provides approximately 70 hours of power reserve when fully wound. Its specified accuracy is +25 to -15 seconds per day when worn on the wrist within a temperature range of 5°C to 35°C.
The movement includes a stop-seconds mechanism for more precise time setting and a date display for everyday use.
Ceramic Bezel and DiaShield Construction
The stainless steel case and bracelet are treated with SEIKO’s DiaShield surface coating. A glossy ceramic bezel insert adds scratch resistance to the unidirectional rotating bezel, while the sapphire crystal has an anti-reflective coating on its inner surface.
The case measures 45.0 mm across, 52.6 mm from top to bottom and 13.4 mm thick. Its diving-oriented construction includes a screw-down crown, screw case back, double-lock clasp and push-button diver’s extension system.
200 m Air-Diving Water Resistance
Designed as a functional mechanical diver’s watch, the SBDC177 provides 200 m air-diving water resistance. The unidirectional bezel, luminous display, screw-down crown and secure bracelet clasp support its purpose-built diving configuration.
Core Shop Japanese Domestic Market Model
SBDC177 is the Japanese domestic reference distributed through the SEIKO Global Brand Core Shop network. Core Shop exclusivity describes its authorized retail channel and does not mean that this is a numbered limited edition. The watch’s Japanese Domestic Market classification and its confirmed manufacture in Japan are separate product attributes.
Key Highlights
- Gray-tone gradient dial inspired by the ocean at dawn
- Mechanical automatic Caliber 6R35 with manual winding
- Approximately 70-hour power reserve
- Ceramic unidirectional rotating bezel insert
- Stainless steel case and bracelet with DiaShield
- Sapphire crystal with inner anti-reflective coating
- 200 m air-diving water resistance
- SEIKO Global Brand Core Shop Japanese-market model
Product Specifications
| Brand / Collection | SEIKO PROSPEX |
|---|---|
| Series | Diver Scuba; commonly known as “SUMO” |
| Model | SBDC177 |
| Market | Japanese Domestic Market |
| Country of Manufacture | Japan |
| Edition | SEIKO Global Brand Core Shop exclusive model; not a numbered limited edition |
| Watch Type | Men’s mechanical diver’s watch |
| Display | Analog |
| Dial | Gray-tone gradient dial with date display |
| Case Dimensions | 52.6 mm length × 45.0 mm width × 13.4 mm thickness |
| Weight | Approximately 190 g |
| Case Material | Stainless steel with DiaShield |
| Bezel | Unidirectional rotating bezel with ceramic insert |
| Crystal | Sapphire crystal with inner anti-reflective coating |
| Case-Back | Screw case back |
| Crown | Screw-down crown |
| Bracelet | Stainless steel with DiaShield; 20 mm width |
| Clasp | Double-lock clasp with push-button diver’s extension |
| Compatible Wrist Size | Up to approximately 195 mm |
| Movement Type | Mechanical automatic with manual winding |
| Caliber | 6R35 |
| Power Reserve | Approximately 70 hours when fully wound |
| Frequency | 21,600 vibrations per hour |
| Jewels | 24 jewels |
| Accuracy | +25 to -15 seconds per day when worn on the wrist at 5°C to 35°C |
| Functions | Date display and stop-seconds function |
| Luminescence | LumiBrite on the hands, indexes and bezel |
| Water Resistance | 200 m air-diving water resistance |
| Magnetic Resistance | Yes |
| Release Date | August 19, 2022 |
| JAN Code | 4954628462435 |