Technical Archive

Eterna
Adventure 7740.40.41.1289— lug 20mm

Eterna Adventure 7740.40.41.1289: 20mm strap. Alligator, box calf, shell cordovan and rubber, cut and stitched in Milano. Choose your leather.

Royal KonTiki GMT Black / Rubber

Artisanal Note

"This model requires a precise 20mm lug width to preserve the original sartorial balance."

Technical Specifications

Eterna 7740.40.41.1289
Lug Width
20 mm

The essential strap measurement.

Browse 20mm straps →
Reference

7740.40.41.1289

Movement

Eterna caliber 3945A Hours, Minutes, Additional 24 Hour Hand (adjustable), Seconds | Date

The Heritage

The Eterna Adventure reference 7740.40.41.1289 is equipped with the Eterna 3945A automatic caliber. The movement offers indication of hours, minutes, seconds, date and an adjustable GMT hand for the second time zone. The GMT function allows the simultaneous reading of two different times through the 24-hour graduated bezel.

FAQ

What is the lug width of the Eterna Adventure 7740.40.41.1289?

The Eterna Adventure 7740.40.41.1289 features a lug width of 20mm. This measurement refers to the distance between the two attachment pins positioned on the case at 12 and 6 o'clock. It is essential to measure the space between the pins accurately, rather than the width of an installed strap, to ensure total compatibility with new artisanal straps.

Which leather strap is best suited for the Eterna Adventure 7740.40.41.1289?

The ideal strap depends on usage and dial variant. For formal-sport environments, we recommend full-grain calf leather with 1.5–1.8mm thickness and semi-polished finishing. For those who appreciate natural patina development, an alligator strap with vegetable tanning evolves into extraordinary aesthetic richness over time. Both options provide perfect compatibility with the 20mm lug width and guarantee durability exceeding ten years with regular maintenance.

How do I change the strap on my Eterna Adventure 7740.40.41.1289?

The procedure is straightforward: use a spring bar tool to remove the attachment pins from the inside of the case. Insert the flat tip of the tool into the access hole, press downward to compress the internal spring, and slide the pin out of the lug hole. Repeat on the opposite side. To install the new 20mm strap, align the holes with the pins and press until you hear the closure click. Verify that both sides are fastened symmetrically.

Are aftermarket straps compatible with the Eterna Adventure 7740.40.41.1289?

Yes, numerous high-quality artisanal aftermarket straps are compatible with the 20mm lug width. We recommend specialist manufacturers with rigorous quality control, such as those offering 0.1mm tolerances on attachment holes. Aftermarket straps enable complete personalisation of the Adventure's aesthetic identity whilst maintaining the technical integrity of the case.

What is the average lifespan of a leather strap for this watch?

A quality leather strap with vegetable tanning maintains structural integrity between 10 and 15 years with appropriate maintenance, including periodic cleaning with a slightly dampened cloth and annual conditioning with specific balms. Prolonged direct sunlight exposure accelerates ageing; excessive humidity can encourage mould formation if the strap remains wet. To extend service life, regularly rotate between multiple straps, allowing the leather to dry thoroughly between uses.