Rolex Explorer 5500 Gilt Double “T < 25" Dial Box and Paper Set

While reference 5500 is best known as the Air-King, Rolex made a fascinating exception between the late 1950s and the late 1960s. During this period, the brand fitted the 34mm Oyster case with the iconic black 3-6-9 Explorer dial and scaled-down Mercedes hands normally reserved for the 36mm Explorer reference 1016. Today, these Explorer-signed reference 5500s rank among the rarest and most sought-after vintage Rolex models.

And that is exactly what we have here: a superb 1960s Rolex Explorer reference 5500. The beautifully preserved 34mm case is matched with an outstanding gilt dial, whose hands and hour markers have developed a wonderfully warm banana-coloured patina over the decades.

What truly sets this example apart, however, is a remarkably rare detail at six o’clock.

Alongside the familiar “Swiss” designation, this dial carries not one but two “T<25” markings. The “T<25” designation indicates the use of tritium as the luminous material while certifying that the watch contained less than 25 millicuries of radioactive material, in accordance with the regulations introduced during the early 1960s.

This was a fascinating transitional period for Rolex. As new international standards came into force, the brand experimented with a variety of dial markings and safety indicators, including the famous Exclamation Point dials, Underline dials, double “T<25” markings such as this one, and several other subtle variations. Today, these small details are cherished by collectors, as they offer a fascinating glimpse into one of the most interesting periods in Rolex’s history.

As if the watch itself weren’t enough, it is accompanied by an exceptional archive of original accessories and documentation, adding another layer of provenance to an already highly collectible Explorer.

Included are the original guarantee booklet, confirming a sale in Great Britain in February 1966, a British-market Rolex booklet dated 1965 bearing the same retailer’s stamp as the guarantee, a rare 1959 Rolex booklet, no fewer than twelve Rolex service invoices accumulated over the decades, and the original inner and outer Rolex boxes.

The watch is paired with one of our own Bulang and Sons leather straps—a combination we think suits this little Explorer perfectly.

History, rarity, and provenance—wrapped into 34mm! 

Specifications:

• Rolex Explorer Reference 5500

• 34mm steel case, smooth bezel

• Serial 1215xxx dating to 1965

• Gilt dial with rare double “T<25” markings

• Bulang and sons leather strap

• Booklets, ,Rolex Service invoices , Rolex inner and outer boxes

• Guarantee booklet stating a sale in Great Britain 1966

• Fully serviced by our watchmaker

• One-year mechanical warranty

• Free worldwide Fedex Priority shipping