Strap for Master Collection 40 Moonphase Stainless Steel / Black-Roman / Bracelet

The lug width of the Longines Master Collection L2.909.4.51.6 is 21 millimetres. This dimension, also known as ansa measurement, represents the distance between the inner points of the two case lugs. To verify strap compatibility, measure this distance precisely using a digital caliper. On milanostraps.it, the catalogue is filtered for this specific measurement, ensuring total compatibility with your watch.

The choice depends on intended use and aesthetic preference. For formal occasions, alligator in vegetable tanning or shell cordovan represent the most refined solutions, emphasising the silver dial. Calf leather offers the best balance between elegance and daily practicality. For humid or sporting environments, NATO straps in woven nylon or fluorinated rubber guarantee durability. The Casati Milano atelier creates bespoke straps with personal leather selection and design updates via WhatsApp.

To change the strap, remove the spring bars connecting the strap to the case lugs. Use a dedicated spring bar tool to compress the pin and lever gently under the lug. Once the previous strap is removed, insert the pins into the new strap, aligning them with the lugs and allowing the pin to snap into position. Always verify that the strap is firmly secured before wearing the watch. If inexperienced, entrust the operation to a specialist watchmaker.

Any strap with a 21mm lug width is compatible with the Longines Master Collection L2.909.4.51.6. On milanostraps.it you will find a curated selection of artisan straps in alligator, calf, shell cordovan and technical materials, all tested to ensure precise fit and construction quality. Straps are customisable in size, initials and stitching thread choice, with rapid shipping and hassle-free returns within 14 days.

The lifespan of a leather strap depends on the material, daily use and maintenance. Vegetable-tanned alligator, if subjected to regular care (neutral cleaner, natural drying, protection from moisture and heat sources), lasts 3-5 years with daily wear. Shell cordovan, due to its superior density, can reach 5-7 years. Calf leather has an average lifespan of 2-4 years. Artisan straps from milanostraps.it include an 18-month warranty on stitching and pin retention. Careful maintenance significantly extends the strap's life, transforming it into an object that ages nobly alongside your watch.