SEIKO PROSPEX SKY SRPB61K1 NAVITIMER ORIGINAL UNBOXING - YouTube
Seiko SRPB61 Sky Prospex - review - YouTube
My Eastern Watch Collection: Seiko Prospex Sky Slide Rule Bezel SRPB61K1 Navitimer (similar to SRPB57 and SRPB59) - A Manual Computer with Limited Use, A Review (plus Video)
Seiko Prospex Sky Slide Rule Bezel SRPB61K1 Navitimer - movement of the seconds hand - YouTube