Strap for Master Collection 38.5 Day Date Stainless Steel / Black-Roman / Bracelet

The lug width of the Longines Master Collection L2.755.4.51.6 is 20mm. This measurement is standardised by the manufacturer and corresponds to the internal distance between the two lugs of the case. Any 20mm strap will sit correctly in the lugs without excessive play or forced fitment.

The best strap depends on intended usage. For formal elegance, an alligator strap in vegetable tanning in medium brown or black tones offers a balance between aesthetics and durability. Shell cordovan represents the premium alternative if you appreciate patina development. For daily wear, a calf leather dyed in the cask in dark brown ensures colour stability and practicality.

Changing the strap requires a dedicated tool (spring bar tool) to compress and remove the retention springs (spring bars) from the case lugs. Insert the small hook of the tool into the groove of the spring bar, gently compress it towards the case interior and simultaneously extract the lug from the opening. Repeat the procedure from the other lug. Install the new strap by reversing the procedure.

Yes, any artisanal strap of 20mm width is compatible with the L2.755.4.51.6, provided that the lug openings present correct construction tolerances and that the leather thickness does not exceed 2.5-3mm at the opening. Quality straps produced by specialist craftsmen meet these parameters and fit smoothly.

The durability of a leather strap depends on tanning quality, frequency of wear and environmental conditions. A quality alligator or shell cordovan strap typically lasts 4-6 years of regular wear. A calf leather dyed in the cask usually lasts 3-4 years. Exposure to humidity, direct heat and perspiration accelerates ageing. Rotating between multiple straps significantly extends the life of each.