Strap for Master Collection 40mm Power Reserve Stainless Steel / Black-Roman / Bracelet

The Longines Master Collection L2.908.4.51.6 features a lug width of precisely 21mm. This measurement refers to the internal distance between the two attachment pins. A compatible 21mm strap will fit snugly within the lugs without lateral play or excessive tension. Always verify the measurement with a digital calliper before purchasing an aftermarket strap.

The optimal choice depends on your usage pattern and dial variant. For formal occasions, we recommend alligator in black or deep brown with uniform patina, emphasising the Swiss elegance of the timepiece. For daily versatility, grained calf leather in brown or taupe offers tactile comfort and adaptability. For sport and aquatic environments, premium rubber ensures durability. A woven fabric NATO in navy or grey represents the most versatile solution for frequent strap changes.

Strap replacement requires a spring bar tool, a specialised watchmaking instrument. Position your watch on a stable surface. Insert the flat tip of the spring bar tool into the small hole beneath the lug, gently pushing the pin inward. Once the pin is released, the strap can be removed. To install the new strap, align the pins with the holes and push until they click into position. Avoid abrupt movements to prevent scratching the case.

Yes, any quality strap with a 21mm lug width is compatible with the L2.908.4.51.6. Milanostraps offers handcrafted straps customisable in alligator, calf, rubber, and fabric. Compatibility is guaranteed by the 21mm lug width specification. We recommend straps with classical construction (double leather stitching or deployant steel buckle) to preserve the aesthetic integrity of the Swiss timepiece.

A quality leather strap, such as alligator or artisanal calf, typically lasts 3–5 years with regular daily wear. Longevity depends on climate, sun exposure, washing frequency, and maintenance. Vegetable-tanned leathers naturally patina, enhancing aesthetic appeal over time. Rubber or fabric-rubber straps offer superior durability (5–10 years) due to UV and moisture resistance. Casati Milano provides an 18-month warranty on custom straps, with options for refurbishment and restoration.