Seiko Essentials Collection - SRPH87From the Essentials Collection. Adding classic automatic timekeeping to the Essentials Collection, this versatile timepiece winds with the movement of the wearers wrist, and never needs a battery. Visible through the screwdown see through caseback, the 23 jewel movement beats at a frequency of 21,600 vibrations per hour, with a power reserve of approximately 41 hours and manual winding capability. With a sophisticated sunray finish, the blue dial