Strap for Flagship Chronograph Two Tone Diamond

The lug width of the Longines Flagship L4.803.3.37.7 is 20 millimetres. This width is measured as the free space between the two spring bars on the watch case where the strap is inserted. A 20mm strap is fully compatible with this model and ensures the correct aesthetic proportion between case and strap.

The Longines Flagship L4.803.3.37.7 pairs perfectly with straps in classic alligator (cognac or dark brown), shell cordovan for those who appreciate patina development, or vegetable-tanned leather for a sustainable choice. Alligator remains the most versatile material for both formal and everyday wear, whilst cordovan is ideal for those seeking a finish that improves over time. Artisanal straps in these materials, constructed with 20mm lugs, maintain the proportional balance of the case.

The strap is attached to the case via two positive spring bars on the lateral lugs. To remove the strap, use a dedicated spring bar tool or consult a professional: press the small release button on one side of the lug, extract the spring, then release the strap. The reverse process secures the new strap. The 20mm lug width remains constant between all compatible straps.

Yes, the Longines Flagship L4.803.3.37.7 is fully compatible with artisanal aftermarket straps of 20mm lug width. Straps crafted from premium materials (alligator, shell cordovan, vegetable-tanned leather) often offer superior construction quality to factory straps and allow aesthetic customisation. Always verify that the lug width is specified as 20mm by the manufacturer.

A quality artisanal leather strap (alligator, cordovan, vegetable-tanned calf) typically lasts 3–5 years with daily wear, provided it receives regular maintenance: avoid prolonged exposure to water, humidity, and heat sources. Natural leather ages, developing patina and minor creasing that form part of its aesthetic value. With proper care and alternated use with other straps, longevity can exceed 5 years. Rubber or NATO fabric materials offer similar durability but require less maintenance.