Prospex Speedtimer Mechanical. 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 models of the past, this powerful creation delivers exceptional timekeeping combined with sporty elegance and wearing comfort. Framed by a countdown timer dial ring that can be utilized to measure the remaining time of a particular event, the hairline-finish blue gray dial displays the word “Speedtimer,” honoring Seiko’s legacy of sports timing. The sporty dial, conjuring images of neoclassic sports cars, is accented by an orange-tipped second hand and offers a date calendar and LumiBrite hands and markers for outstanding visibility in low light conditions. With an upgraded power reserve of approximately 72 hours, 3 full days, the 24-jewel automatic movement beats at a frequency of 21,600 vibrations per hour with manual winding capability. Crafted of stainless steel with super-hard coating, this rugged yet refined watch is 200 meter water resistant while boasting the slimmest case of any Seiko 6R model, flowing seamlessly from the case to the patterned leather strap. Topped with a curved sapphire crystal with anti-reflective coating on the inner surface, it includes a screwdown caseback and a tri-fold push button release clasp.