SLA025 vs SLA023
Geth put them head to head in "Seiko SLA025 VS SLA023". Scores, specs and verdicts side by side.
Seiko · Prospex
Seiko SLA025 Hi-Beat 1965 Re-creation
10/10
Unreal scenario
His favourite watch ever: a mesmerising Zaratsu case and Hi-Beat sweep, Seiko magic incarnate, but it scratches if you look at it and has no bracelet.
Seiko · Prospex Marinemaster
Seiko SLA023 Marinemaster 300
9/10
Beyond thunderdome
His grail and favourite Marinemaster: an unmatched Zaratsu case, the best bezel action and handset he's ever known and Christmas-tree lume. The Prospex X, the painted triangle and the unregulated movement are the only things stopping it being perfect.
The winner: Seiko SLA025 Hi-Beat 1965 Re-creation
I love them both and I know how lucky I am to have them on the beef wagon. The 023 wins on loom, but the 025 is my favourite Seiko watch. I've had more or less all the SLAs and the Tunas, and this one is beyond Thunderdome.
Spec sheets
| SLA025 | SLA023 | |
|---|---|---|
| case diameter (mm) | 44.8 | 44.3 |
| thickness (mm) | 15.7 | 15.4 |
| lug to lug (mm) | 51.4 | 50 |
| lug width (mm) | 19 | 20 |
| weight (g) | – | 222 g with all links (about 205 g with a link out each side), said of both MM300s stated by gethin |
| case material | Steel; mirror Zaratsu polish everywhere except the top of the case/lugs; monocoque; drilled lugs (he thinks the original wasn't drilled); 1 mm thicker than the original; no applied logo | 316L stainless steel ('I believe') with Diashield coating (about 500 Vickers vs 250), duller and greyer than the SBDX001; monocoque case, brushed midcase, Zaratsu polish on the top of the flanks, drilled lugs |
| crystal | Double-domed sapphire, AR coating | Flat sapphire with an internal dome (AR coating inside) |
| water resistance (m) | 300 | 300 |
| crown | Unsigned crown, faithful to the original (earlier draft said 'horseshoe crown'; see notes) | Screw-down, signed (laser-etched 'Prospex X'), at 4 o'clock |
| caseback | Monocoque (horseshoe-shaped back) | Monocoque, no removable caseback; tsunami wave on the back. Not limited. His is a March 2021 J1 |
| bezel | Lacquered, coin-edged (not ceramic) | 120-click unidirectional, ceramic insert, coin-edged; unprotected painted lume triangle instead of a shrouded pip, lumed to the 20-minute marker. His has a dent from a car seatbelt buckle; Seiko quoted GBP 500 for a replacement bezel. In the Jan 2023 strap video he also says it is 'slightly misaligned' |
| dial | Matte black, gold-coloured printed indices, gold-framed date box at 3, printed (no applied parts); traffic-light seconds hand; no Prospex X | Navy blue sunburst: almost black indoors, bright sunburst in sunlight; gold seconds hand (lumed lollipop) and gold '300m' text; indices look applied but he hears they are stamped from the back; Prospex X on dial; ISO sliver/marking near 3 o'clock on post-March 2021 examples like his |
| date | 3 o'clock, gold frame | Yes, at about 4:30 (date window with a sliver, per hOuORgMFkZ8) |
| movement | Seiko 8L55 Hi-Beat, 5 Hz / 36,000 vph, 37 jewels, 55 h power reserve, -10/+15 s/day (stated, to verify); Shizukuishi; a simplified, less decorated 9S85. Mr Jun's first example ran 0 s/day on wrist, +1 in the watchbox | Seiko 8L35B, 26 jewels, 28,800 vph, hacking and hand-winding, 50 h power reserve, based on the 9S55, about 192 parts, hand assembled at the Shizukuishi studio, MEMS escapement parts, SPRON springs; rated +15/-10 s/day, not regulated. His has run about +2 to +6 s/day across videos |
