Seiko Presage x Automatic ft. Classic Series aka Open Heart aka Ai-Iro Men Formal Round 100m Water Resistant Watch SPB527J1 SPB527 SPB-527 SPB-527J1Experience the Seiko Presage SPB527J1 Ai-iro with its captivating open-heart dial showcasing the intricate 6R55 automatic movement through a window in the stunning indigo silk-textured dial. This 40.2mm timepiece combines Japanese heritage with modern watchmaking, featuring dual-curved sapphire crystal, 100m water resistance, and a sophisticated multi-row stainless steel bracelet that offers both vintage inspiration and contemporary comfort.Caliber Number / Movement6R5J (automatic with manual winding capacity)Power Reserve / AccuracyApproximately 72 hours (+25 to -15 seconds per day)CrystalSapphire crystal (dual-curved, anti-reflective coating)LuminousNilCase / Band MaterialStainless steel (super hard coating) case with stainless steel band (deployment clasp with push-button release)Water Resistance100m / 10 barCase SizeThickness: 13.0 mmDiameter: 40.2 mmLength: 46.0 mmLug width: 20.0 mmOther SpecificationsSeiko Presage x Automatic ft. Classic Series aka Open Heart aka Ai-IroMade in JapanMagnetic resistance (4,800 A/m)See-through case backScrew case back24 jewels24-hour displayStop second hand function (hacking mechanism)Regular timekeeping (analog display)