This is the SD1971 which pays tribute to the Sumo Diver watch.There are a few theories as to how the Sumo got its name but one interesting one is that the marker at 12 looks like the "mawashi" worn by Japanese Sumo wrestlers during a match.This is lovely looking watch with real presence and benefits from the following spec:
 
 
2020 Brand New model
Sapphire Crystal Glass
NH35 Automatic Movement
120 Click Rotational Ceramic Bezel
200m Water Resistance
Screwdown Crown
Screwback Case
316L Stainless Steel Case
Stainless Steel Strap with extra Rubber Strap 
Hacking Movement
C3 Luminova on the face