The Seiko 5 Sports SRPK31K1 'SKX Midi' is a compact and versatile automatic sports watch inspired by the iconic SKX diver series, offering a smaller footprint for enhanced everyday wearability while maintaining robust functionality. This model features a 38mm stainless steel case with brushed and polished finishes, a unidirectional rotating stainless steel bezel with a black insert, and a see-through screw-down case back to showcase the in-house movement. The cream sunray dial includes luminous hands and indexes with LumiBrite for excellent low-light visibility, along with a day-date window at 3 o'clock. Powered by the reliable Caliber 4R36 automatic movement with hacking seconds and manual winding capability, it offers a 41-hour power reserve and 24 jewels for smooth operation. Completed with a stainless steel bracelet featuring a three-fold clasp with push-button release and secure lock, and 100 meters of water resistance, this timepiece is ideal for casual adventures, sports, and daily use, blending classic dive-watch styling with modern proportions.
| Category | Details |
| Model | SRPK31K1 |
| Collection | 5 Sports SKX Midi |
| Movement | Automatic Mechanical, Caliber 4R36 (24 jewels, 21,600 vph) |
| Accuracy | -35 to +45 seconds per day |
| Power Reserve | Approximately 41 hours |
| Functions | Hours, minutes, seconds, day-date (window at 3 o'clock), hacking seconds, hand-winding |
| Dial | Cream sunray, with LumiBrite luminous hands and indexes |
| Case Material | Stainless steel |
| Case Diameter | 38 mm |
| Case Thickness | 12.1 mm |
| Lug Width | 20 mm (drilled lugs for interchangeable straps) |
| Lug-to-Lug | 44.2 mm |
| Crystal | Hardlex |
| Case Back | See-through screw-down |
| Crown | Screw-down |
| Bezel | Unidirectional rotating, stainless steel with black insert |
| Bracelet | Stainless steel, three-fold clasp with push-button release and secure lock |
| Water Resistance | 10 BAR / 100 meters / 330 feet (suitable for swimming and snorkeling) |
| Weight | 140 g |
| Additional Features | Magnetic resistance 4,800 A/m |
Seiko Dial Markings Note:
This Seiko watch has a "K" suffix, meaning it's built for international markets and assembled at Seiko's quality facilities outside Japan (e.g., Malaysia).
That's why the dial lacks "Made in Japan" or "Japan Movement"—standard for these models. It does not impact authenticity, quality, or performance.