Essentials Collection From the Essentials Collection. Adding classic automatic timekeeping to the Essentials Collection, this versatile timepiece winds with the movement of the wearer’s 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 includes a calendar and crisply defined hands and markers. Crafted of stainless steel, with tri-fold push button release clasp. 10 bar, 100M Water Resistant. Dial Colour Blue Movement Caliber Number 4R35 Movement Type Automatic with manual winding Power reserve Approx. 41 hours Jewels 23 Functions Stop second hand function Date display Case/Band Case Size Thickness:11.8mmDiameter:41.2mmLug-to-lug:48.5mm Crystal Hardlex Clasp Three-fold clasp with push button release Distance between lugs 20 Other Details Water Resistance 10 bar Weight 130.0g Features See-through & Screw case back