Specifications
- Movement
- Seiko 4R36, automatic with hand winding
- Accuracy
- +45 to -35 sec/day
- Case diameter
- 42.5 mm
- Lug-to-lug
- 46.0 mm
- Thickness
- 14.2 mm
- Lug width
- 22 mm
- Case
- Stainless steel
- Crystal
- Hardlex
- Water resistance
- 100 m
- Magnetic resistance
- 4,800 A/m
- Weight
- 169 g
- Band length (max)
- 205 mm
- Clasp
- Three-fold clasp with push button release
- Lume
- LumiBrite on hands and index(es)
- Dial
- White
- Features
- See-through & Screw case back, Three-fold clasp with secure lock, Unidirectional rotating bezel
- Released
- 2026-08
- Series
- Seiko 5 Sports, SKX series
Same case, other dials
Identical case, movement and dimensions; only the dial, bezel or finish differs.
Other watches on the 4R36
Questions
Is there a Japanese version of the Seiko HDB004?
The Japanese Seiko site lists no model with the same calibre, case and dial, so the HDB004 has no Japanese domestic twin in the current lineup.
What movement is in the Seiko HDB004?
The HDB004 runs on the Seiko 4R36, an automatic movement that can also be wound by hand. See the 4R36 page for its specs and every watch built on it.
Does the Seiko HDB004 have a sapphire crystal?
No. The HDB004 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 HDB004?
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 HDB004?
22 mm. Any 22 mm strap fits.