As well as local time, this enables the time in a second time zone to be read simultaneously by means of an independent central hand which makes one revolution of the dial in 24 hours. GMT is short for Greenwich Mean Time, the time at the Greenwich Royal Observatory, which is the universal reference point for calculating time zones.

The Luminor 1950 3 Days GMT 24H is the first watch from Officine Panerai to adopt a new manufacture movement, the automatic P.9003 calibre. This is a development of the P.9001 calibre, with which it has many useful functions and excellent features in common. The main innovation relates to the GMT function, which is indicated over 24 hours instead of 12 hours; it also has a newly designed circular power reserve indicator on the back of the watch, which is very visible and easy to read through the sapphire crystal in the caseback.

The power reserve is three days, achieved by two spring barrels connected in series, and the oscillating mass rotates in both directions, making the automatic winding mechanism very efficient. In terms of regulation, the hour hand – connected to the date – can be moved independently and in jumps of one hour, without interfering with the minute and seconds hands; equally, when setting the time the device which stops the balance and zeroes the seconds hand comes into operation, so that the time can be exactly synchronised with a reference signal.

The GMT 24H function is also evident in the design of the black dial: as well as the classic markers for reading the local time, the outermost part of the dial carries the figures for reading the second time zone, indicated by the hand with an arrow. The clarity and legibility of the dial, which also contains the date window and the small seconds counter at nine o’clock, are ensured in the poorest lighting conditions by its sandwich structure: the luminous substance is contained between two discs and shines through holes in the upper one corresponding to the markers. This type of construction has been used by Panerai watches since the 1930s and confirmed over the years as a distinctive mark of the Florentine brand.

Another iconic element of the brand is the device protecting the winding crown with the locking leaver, revived in the Luminor 1950 3 Days GMT 24H in its most classic version: it is made of brushed steel contrasting with the polished steel of the case. The Luminor 1950 case 44 mm is AISI 316L steel, which is stainless with a low carbon content and particularly resistant to corrosion.

Water-resistant to 30 atmospheres (a depth of about 300 metres ), the Luminor 1950 3 Days GMT 24H is fitted with a black leather strap with ecru stitching. It is supplied with a spare rubber strap, a steel screwdriver and the tool for replacing the strap, an operation that is simply carried out thanks to the push-pieces in the lugs.