Specifications
- Movement
- Seiko 4R34, automatic with hand winding
- Accuracy
- +45 to -35 sec/day
- Case diameter
- 39.4 mm
- Lug-to-lug
- 47.9 mm
- Thickness
- 13.6 mm
- Lug width
- 20 mm
- Case
- Stainless steel
- Crystal
- Hardlex
- Water resistance
- 100 m
- Magnetic resistance
- 4,800 A/m
- Weight
- 147 g
- Band length (max)
- 205 mm
- Clasp
- Three-fold clasp with push button release
- Lume
- LumiBrite on hands and index(es)
- Dial
- Green
- Features
- See-through & Screw case back, Three-fold clasp with secure lock
- Released
- 2026-06
- Series
- Seiko 5 Sports, Field series
Same case, other dials
Identical case, movement and dimensions; only the dial, bezel or finish differs.
Other watches on the 4R34
Questions
Is there a Japanese version of the Seiko HDB001?
The Japanese Seiko site lists no model with the same calibre, case and dial, so the HDB001 has no Japanese domestic twin in the current lineup.
What movement is in the Seiko HDB001?
The HDB001 runs on the Seiko 4R34, an automatic movement that can also be wound by hand. See the 4R34 page for its specs and every watch built on it.
Does the Seiko HDB001 have a sapphire crystal?
No. The HDB001 has a Hardlex crystal. Hardlex is Seiko's hardened mineral glass: tougher than plain mineral glass, softer than sapphire.
How water resistant is the Seiko HDB001?
100 m (10 bar). That covers swimming and snorkelling; it is not a certified diver's watch unless Seiko says so.
What is the lug width of the Seiko HDB001?
20 mm. Any 20 mm strap fits.