The Bronze Field Guide

Steeldive SD1975S Bronze Tuna Diver

The Steeldive SD1975S Bronze Tuna Diver is a current-production diver watch with a cusn8 bronze case. It measures 47.5 mm across, 15 mm thick, 44 mm lug to lug, 103 g, and is water resistant to 300 m. Inside is the Seiko NH35 automatic movement, with 41 hours power reserve. Complications: Time only. Priced from $189. Brand origin: China.

Bronze diver watchesCuSn8DiversUnder $500
Reference
Type
Diver
Price
$189
Case diameter
47.5 mm
Thickness
15 mm
Lug-to-lug
44 mm
Water resistance
300 m
Weight
103 g (head only)
Origin
China
Movement
Automatic
Caliber
Seiko NH35
Power reserve
41 hours
Complications
Time only
Ceramic
CuSn8 marine bronze
Colour
Hardness
Construction
Assembled
Surface treatment
Caseback
Nickel-free
Not verified (contact-point materials not all confirmed)
Bracelet / strap
Leather or rubber strap with bronze buckle
Ceramic bracelet
Crystal
Single domed sapphire
Display back
No
Dial
Black (MarineMaster homage)
Lume
Super-LumiNova C3 and BGW9
Availability
Offered
Status
Current
Medium confidence Verified Jul 2026 Source: Steeldive official store / The Time Bum Maker / listing ↗
Facts are free to cite with a link.
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Frequently asked questions

What bronze alloy is the Steeldive SD1975S Bronze Tuna Diver?

The Steeldive SD1975S Bronze Tuna Diver has a cusn8 bronze case. It is recorded at medium confidence pending a maker-stated alloy.

What size is the Steeldive SD1975S Bronze Tuna Diver?

It is 47.5 mm in diameter, 15 mm thick, 44 mm lug to lug, and water resistant to 300 m.

How much does the Steeldive SD1975S Bronze Tuna Diver weigh?

About 103 g (head).

How much does the Steeldive SD1975S Bronze Tuna Diver cost, and is it available?

It is current-production and lists from $189.

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