Released in 2017, the Mk IV Vanguard had markedly improved build quality and darkness visibility. The first Mk IV models, which had 42mm cases, featured the SuperSandwich™ dial that's filled to the brim with Swiss Super-LumiNova, to achieve the best darkness visibility ever on a Gruppo Gamma timepiece.

Visually, the most prominent change from Mk III to Mk IV was the design of the numeric markers on the dial.

Models (2017-): A-05

Case: 316L stainless steel/ CuSn8 bronze, diameter 42mm/ 44mm, lug width 22mm/ 24mm

Bezel: 316L stainless steel, fixed/ 120-click unidirectional, marker filled with Swiss Super-LumiNova

Crystal: Sapphire, double-domed, anti-reflective

Water resistance: 200m/ 660ft

Movement: Seiko NH35A/ ETA 2824-2

Dial: Markers filled with Super-LumiNova

Hands: Hour/ minute and red seconds, filled with Super-LumiNova