Strap for Master Collection Power Reserve

The lug width of the Longines Master Collection L2.666.4.51.6 is 20mm. This measurement refers to the distance between the two metal protrusions on the watch case where the strap is attached. This 20mm specification was deliberately chosen by Longines to maintain visual proportion between the 42mm case diameter and the strap, ensuring harmonious aesthetics.

The optimal strap choice depends on intended usage. For formal elegance, an alligator strap in dark brown or black remains the classical choice due to its natural texture and ability to develop patina over time. For daily versatility, vegetable-tanned calf leather offers practicality and environmental consciousness. A NATO canvas strap is ideal for sports or nautical contexts while maintaining correct visual proportions.

Strap replacement requires a specialized tool (spring bar tool or strap removal bar). Position the watch so the lugs are visible, insert the tool into the space between the lug and case, apply gentle pressure to release the internal spring, then remove the lug pin. Repeat on the opposite side. Insert the new strap and verify secure fastening.

Yes, any strap with a 20mm lug width is fully compatible with your Master Collection L2.666.4.51.6. Aftermarket straps offer aesthetic freedom and customization beyond the original Longines strap while maintaining complete mechanical compatibility. Always verify lug width before purchase.

A quality leather strap (alligator, calf, shell cordovan) typically lasts 3-5 years with moderate daily use, extending to 7-10 years with occasional wear. Longevity depends on sun exposure, humidity, mechanical wear, and maintenance practices. Regular cleaning with a soft, dry cloth and avoiding water immersion significantly extends strap lifespan.