Seiko
Mechanical SRPA29— lug 20mm

The Seiko SRPA29 has a 20mm lug width, a specific measurement that balances the 42mm case diameter with the case architecture. To verify, measure the linear distance between the two lug holes with a caliper: it should register exactly 20mm.

The choice depends on usage: alligator offers regular grain and sporty elegance; full-grain calf develops natural patina over time; NATO guarantees daily practicality and water resistance; FKM rubber maintains consistent readability without variations. On military blue dials we recommend dark blue alligator or havana calf; on black dials, black calf or dark brown alligator.

Remove the watch from your wrist. Using a spring bar tool, apply pressure from bottom to top on the small pins that hold the strap to the lugs. Once the pins are extracted, the strap will come free. Insert the pins into the new 20mm strap and reinsert into the lugs until you feel the click.

Yes. Any strap with a 20mm lug width is compatible with the Seiko SRPA29, provided it is built with artisanal quality: the lugs must be perfectly vertical with no play, and the strap must fit fluidly into the case receptacles. Our 20mm straps meet these specifications.

A high-quality full-grain calf strap maintains structural integrity for 3-5 years of daily use, developing natural patina. Longevity depends on exposure to moisture and mechanical stress. Alligator, being denser, can last 5-7 years. FKM rubber maintains elasticity for 2-3 years before requiring replacement.