In 1968 a Japanese saturation diver complained to Seiko that all the existing diver watches were not strong enough to withstand heavy impact and prolonged periods of deep underwater pressure. After seven years of development Seiko launched the “perfect professional divers' watch” in 1975. One of its innovative features is the ceramic protective shroud that makes the watch extremely robust and also very distinctive. Aficionados of Seiko watches thought it looked like the wearer had a can of tuna strapped to his wrist, hence the nick-name, “Tuna”.
 
This is the "Emperor Tuna" for those who think the normal one just doesn't cut the mustard when it comes to size with a huge 52mm case and 17.85mm thickness.
 
It’s a very big watch - though the relatively short lug to lug width means it’s not impractically so - and people either love ‘em or hate ‘em. It’s ironic a watch that looks like a can of tuna should be such a “Marmite” timepiece.
 
The Black SD1978 benefits from the following spec:
 
Sapphire Crystal Glass
NH35 Automatic Movement
120 Click Rotational Ceramic Bezel
1000m Water Resistance
Screwdown Crown
Screwback Case
316L Stainless Steel Case
Stainless Steel Engineer Strap fitted and free Rubber Strap also supplied
Hacking Movement
C3 Luminova on the face
Lug width - 22mm
Case Diameter - 53mm
Lug to Lug - 47.5mm
Case Thickness - 17.8mm
Weight - 285g
Hard Presentation Box and warranty card
 
We also supply a free Steeldive branded rubber strap with fitting tool and extra pins so you can give the watch a different look if you want.