Seiko 5 Sports SKX Series SRPJ45K1 Skeleton Style Automatic Blue Transparent Dial Stainless Steel Men's Watch

The Seiko SRPJ45K1 is a distinctive member of the Seiko 5 Sports SKX Series, inspired by the iconic 1970s Seiko Time Sonar. Its standout feature is the transparent blue skeleton-style dial, allowing a partial view of the rotating day-date discs beneath the dial—an unmistakable tribute to the original Time Sonar design. The watch is further enhanced with a vibrant orange central seconds hand, LumiBrite-filled hands and hour markers, and a matching blue unidirectional bezel, creating a bold yet highly wearable sports watch.

The watch features a 42.5mm stainless steel case with a compact 46.0mm lug-to-lug measurement and 13.4mm thickness, making it comfortable despite its sporty proportions. A Hardlex crystal protects the transparent dial, while the stainless steel bracelet is secured by a three-fold clasp with push-button release. The see-through screw case back showcases the automatic movement, and 100 metres of water resistance ensures dependable performance for everyday wear and recreational swimming.

Inside is Seiko's proven Caliber 4R36 automatic movement, featuring 24 jewels, manual winding, and hacking seconds for accurate time setting. The movement provides approximately 41 hours of power reserve and displays both the day and date at 3 o'clock. The 4R36 is widely respected for its durability, reliability, and ease of servicing, making it one of Seiko's most trusted modern mechanical calibers.

The SRPJ45K1 has become one of the most recognizable modern Seiko 5 Sports models thanks to its retro-inspired transparent dial and Time Sonar heritage. It offers a unique combination of vintage design, robust mechanical performance, and everyday practicality, making it a favorite among Seiko enthusiasts and collectors.