Specifications
- Movement
- Seiko 4R34, automatic with hand winding
- Accuracy
- +45 to -35 sec/day
- Case diameter
- 42.5 mm
- Lug-to-lug
- 46.0 mm
- Thickness
- 13.6 mm
- Case
- Stainless steel, see-through case back
- Crystal
- Hardlex
- Water resistance
- 100 m
- Magnetic resistance
- Magnetic resistant
- Weight
- 161 g
- Band length (max)
- 210 mm
- Clasp
- One-push three-fold clasp
- Lume
- LumiBrite on hands and index(es)
- Dial
- Black
- Features
- Double-lock clasp, Rotating 24-hour bezel, See-through & Screw case back
- Released
- 2025-08
- Series
- Seiko 5 Sports, SKX series
Same case, other dials
Identical case, movement and dimensions; only the dial, bezel or finish differs.
- SBSC017 White · 42.5 mm · 4R34
- SBSC019 Green · 42.5 mm · 4R34
- SSK001 JP SBSC001 Black · 42.5 mm · 4R34 $495
- SSK003 JP SBSC003 Blue · 42.5 mm · 4R34 $495
- SSK005 Orange · 42.5 mm · 4R34 $495
- SSK017 Yellow · 42.5 mm · 4R34
- SSK019 Gray · 42.5 mm · 4R34
- SSK021 Gray · 42.5 mm · 4R34
- SSK033 Silver · 42.5 mm · 4R34 $495
- SSK035 Green · 42.5 mm · 4R34 $495
- SSK036 JP SBSC020 Black · 42.5 mm · 4R34 $475
- SBSC015 42.5 mm · 4R34 Discontinued
Other watches on the 4R34
Questions
What movement is in the Seiko SBSC021?
The SBSC021 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 SBSC021 have a sapphire crystal?
No. The SBSC021 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 SBSC021?
100 m (10 bar). That covers swimming and snorkelling; it is not a certified diver's watch unless Seiko says so.