Prospex Speedtimer Mechanical Chronograph. Seiko Prospex challenges every limit with timepieces created to exceed expectations, engineered with superior style and innovative technology for the sea, sky, or land. Driven by a heritage of iconic design, Prospex continues to keep going forward with excellence in precision timekeeping, crafted for the modern world. Based on Seiko’s Speedtimer chronographs of the early 1970’s, this powerful creation offers exceptional timekeeping combined with sporty elegance and wearing comfort. The sky-blue patterned dial, framed by a tachymeter scale, displays high contrast subdials and a blue chronograph hand designed to evoke images of endless coastal highways as it smoothly sweeps, as well as a date calendar and LumiBrite hands and markers for outstanding legibility in low light conditions. Delivering chronograph measurement of up to 12 hours of elapsed time in 1/8-second increments, the proprietary caliber 8R48 34-jewel automatic movement beats at a frequency of 28,800 vibrations per hour, with a power reserve of approximately 45 hours and manual winding capability. The movement includes a column wheel and vertical clutch mechanism allowing for smooth, stutter-free movement of the chronograph hand while providing long-term efficiency, reducing wear and tear and maintaining the power reserve better during chronograph operation. For reliable timing, the three-pointed hammer system ensures that all hands return to zero instantly and in perfect synchronization when the re-set pusher is pressed. Crafted of stainless steel with a super-hard coating and paired with a multi-row bracelet for a note of tailored luxury, this extraordinary timepiece also features a dual-curved anti-reflective sapphire crystal, screwdown caseback, and tri-fold push button release clasp. 10 bar, 100M Water Resistant