The 79470 is the Black Bay Pro, introduced in 2022. It combines the proportions of the 39 mm Black Bay family with a fixed steel bezel carrying a 24-hour scale and a yellow GMT hand. That makes it more sober and robust than the Black Bay GMT, which has a coloured rotating bezel and measures 41 mm.
The in-house calibre MT5652 has an independently adjustable hour hand, so on arrival in another time zone you set the local time without disturbing the GMT hand or the minutes; the date follows the local time. The power reserve is about 70 hours and the movement is COSC-certified. The case is slightly thicker than that of the Fifty-Eight, the dial is black with large luminous indices, and the watch is water-resistant to 200 metres.
On a pre-owned example we test the GMT function and the date, and look at the steel bezel, which shows wear but cannot crack as ceramic can, at the bracelet and clasp, and at the set. For a version on a strap we state whether the original buckle is present.