⌕

Videos / Line-ups / Head to head

Seiko SLA023 VS Sinn U1 Tegimented. 2.8k diver battle

Head to head

Seiko SLA023 VS Sinn U1 Tegimented. 2.8k diver battle

2 watches · 18:29 · 2023-10-27 · 1,535 views

German tank versus Japanese warlord: the £2,800 diver battle nobody wins

Two twerps, basically the same money, both around £2,800 British. On one side the Sinn U1, fully tegimented, 1,000 metres, hex-screw H-link, a bead-blasted German submarine-steel freak. On the other my Seiko SLA023 Marine Master 300, blue dial, zaratsu polishing, the bezel action of the gods.

I've reviewed them both before, and yes, I was ill and snuffling the whole way through. But this is bauhaus versus Japanese design language, toughness versus beauty, and I had to put them head to head. Lume war at the end, obviously.

Too close to call

I couldn't decide. The Sinn wins on anti-reflective, the bracelet screws and toughness, the Seiko wins on lume, on-the-fly adjustment and that zaratsu design language. Neither one is wrong: I absolutely love both of these pieces.

U1 vs SLA023: scores and specs side by side →

The line-up

1

Sinn U1 Tegimented (full Tegiment)

9/10 · Beyond thunderdome

The anti-reflective is staggering, the hex-screw H-link is quality, it ran plus 6 in 6 days on the winder, but get rid of that stamped clasp with no on-the-fly ratcheting.

▶ Play from 00:43 Full listing →
2

Seiko SLA023 Marinemaster 300

9/10 · Beyond thunderdome

My favourite bezel action I've ever felt, the best handset in history, a blue dial with real depth and a zaratsu case like a mirror, but that bracelet is a one-piece link masquerading as a three-piece.

▶ Play from 09:02 Full listing →

In his words

"It's just an absolute freak of nature."

▶ Play from 08:30

"It's my favourite bezel action I've ever felt."

▶ Play from 10:47

"There are no pretenders here, both of these are insanity."

▶ Play from 14:51

"I absolutely love both of these pieces."

▶ Play from 17:51

More line-ups

The tiers of Seiko

The tiers of Seiko: from the SKX up to the MM300, one rung at a time

8 watches · 2026-02-14 · 2,250 views

Seiko Marinemaster Bonanza Life. SLA019, SLA047, SLA021, SLA023

Marinemaster bonanza life: SLA019, SLA047, SLA021 and SLA023

4 watches · 2025-12-27 · 3,574 views

Head to head10:41

SBDX001 VS SLA023. Similar yet different

SBDX001 vs SLA023: the original Marinemaster shows the new one how it's done

2 watches · 2025-06-14 · 1,151 views

Head to head15:12

Seiko SLA025 VS SLA023

SLA025 vs SLA023: two of the best Seikos ever, and one is beyond Thunderdome

2 watches · 2025-05-24 · 1,610 views