The G-Shock GW-S5600-1JF is no longer in production, according to the G-Shock Japan database, but it was effectively replaced by the recently released GW-S5600U-1JF. The GW-S5600-1JF was a unique solar-powered square model equipped with exterior metal parts made of titanium and a carbon fiber insert band and keeper. It was known as the most lightweight G-Shock watch at 47 grams. (The women’s GMA-S2100 is lighter, but the GW-S5600-1JF and GW-S5600U-1JF retain the title of the lightest men’s G-Shock.) The GW-S5600-1JF was a Japan-only model, but it was popular as an import in other countries due to its unique status, and we frequently spotted it in watch stores in Hong Kong.
The new GW-S5600U-1JF has the same dimensions, weight, and style as the original, along with an upgraded LED light and an updated module with many improved functions. (See our post on the updated square module series for the full features and differences from the original model.) The other original models that got updates with the “U” series are still in production for now. These include the G-5600E-1JF, GW-5000-1JF, GW-M5610-1JF, GW-M5610-1BJF, and GW-M5610BC-1JF.