Strap for Conquest Classic Moonphase Stainless Steel / Silver

The Longines Conquest Classic L2.798.4.72.3 features a lug width of exactly 21mm. This intermediate measurement is the result of the 42mm case geometry and accommodates straps crafted with artisanal precision. To verify the measurement, position a digital calliper between the inner shoulders of the lugs: you will find 21 millimetres. It is crucial to respect this measurement to the millimetre, as even half a millimetre of deviation results in imperfect fit.

The optimal strap depends on usage and personal preference. For noble expression, we recommend alligator with vegetable tanning: the natural grain texture evolves over time, developing an individual patina. Vegetable-tanned calf leather offers a contemporary, lightweight alternative with understated character. For authentic sports use, high-density cotton NATO or vulcanised rubber maintain the model's original spirit. Avoid synthetic materials or chrome tanning: they would not honour the complexity of the L678.2 movement.

Strap replacement requires minimal tools: a spring bar removal tool or small flat-head screwdriver. Gently unscrew or extract the spring bars securing the strap to the lugs. Remove the old strap, position the new one by aligning the holes, and reinsert the bars carefully, ensuring complete engagement. Do not force: the spring bars must click naturally into place. If uncertain, contact an authorised service centre.

Yes, you may use a quality aftermarket strap constructed for 21mm lugs, provided it is crafted by artisans who understand case proportions and geometry. Compatible straps in vegetable-tanned alligator, vegetable calf, or NATO deliver superior longevity and aesthetics compared to generic options. Always verify that the strap is specifically dimensioned for 21mm: compatibility is a non-negotiable condition.

Longevity depends on leather quality and usage. An alligator strap with vegetable tanning, if properly maintained, lasts 5–8 years and beyond, developing a natural patina that enhances its character. Vegetable-tanned calf leather offers similar durability, 4–7 years, with greater sensitivity to moisture. Regular maintenance—avoiding prolonged immersion, allowing natural drying, occasionally applying leather balm—significantly extends lifespan. NATO and rubber, more robust materials, last approximately 3–5 years, resisting humid environments better but ageing less elegantly.