Seiko's 4R36 mechanical movement beats at a frequency of 21,600 vibrations per hour with manual and automatic winding capabilities and a power reserve of 41 hours Case Diameter: 40.0mm The black dial includes a day/date calendar and stealthy black hands and markers Stainless steel case with black ion finish and matching black nylon strap Water-resistant to 10 bar, 100 meters (300 feet) Case Size :Thickness:11.5mm, Diameter:40.0mm, Lug-to-lug:44.6mm Distance between lugs : 20mm Power reserve : Approx. 41 hours