That looks like a really nice(soft) NATO! Where is it from if you don't mind me asking?
It's a Blu Shark. My favorites are the ToxicNatos N8O series - super soft, the right thickness and plenty long enough. The Blu Shark is a hair thicker and a little short - barely enough to fold back over on a 7.25" wrist.
Have you owned a PhenomeNATO? I bought a BluShark last week and it's too thick for me / the design of the strap is more Panerai than Speedmaster IMO, with its large square pin holes.
Wow...coolest Seiko ever!🥰