{"product_id":"seiko-selection-open-heart-hfb007j-womens-watch","title":"Seiko Selection Open Heart HFB007J Women's Watch","description":"\u003cp data-path-to-node=\"6\"\u003eThe Seiko Selection HFB007J (also designated across Japanese domestic catalogs as the HFB007 within the celebrated Seiko Selection S Series Mechanical Collection) is an exquisitely proportioned, high-performance Japanese automatic mechanical open-heart dress-sports timepiece. Designed as the elegant 33.7mm feminine counterpart and pairing model to the 40.0mm HFB003J, this reference embodies the core design philosophy of the Seiko Selection lineup: an unwavering commitment to everyday versatility, refined aesthetics, and accessible Japanese mechanical craftsmanship. Across horological forums, collector communities, and Japanese watch circles, it has earned defining community nicknames—the \"Open Heart\", \"Black Open Heart\", \"Ladies Open Heart\", \"S Series\", \"Semi-Skeleton\", \"Midnight Open Heart\", or \"Petite Open Heart\"—for its rich radial sunburst black dial, signature open balance-wheel aperture, three-dimensional diamond-cut indices, and slender 33.7mm case architecture. It unites a sculpted 316L solid stainless steel case in a tailored 33.7mm diameter with an ink-black sunray dial face, three-sided cut hour batons, an open-heart mechanical window revealing the escapement, an in-house Japanese automatic mechanical caliber, durable Hardlex crystal glass, certified 100-meter water resistance, and an integrated solid stainless steel construction with an easy-adjust sizing system. Perfectly calibrated for ladies and collectors seeking a sophisticated, mechanical daily wearer that transitions effortlessly from corporate executive meetings and formal presentations to smart-casual evening dinners. The defining visual centerpiece of this HFB007J reference is its multi-layered, sunburst black dial face. Finished with an ultra-fine radial brushing technique, the deep black surface catches and diffuses ambient lighting into subtle charcoal reflections that accentuate optical depth across the compact dial area. Positioned prominently at 9 o'clock is a signature open-heart circular aperture framed by a polished silver-tone chapter ring, offering an unobstructed view into the oscillating balance wheel and pallet fork to showcase the living mechanical heartbeat of the movement. Circling the perimeter are three-dimensional, three-sided faceted applied baton hour markers with wide, rainbow-ground chamfered facets that reflect light with brilliance. Slender silver-tone sword-style hour and minute hands glide over the face alongside a fine central sweep seconds hand, delivering instantaneous, high-contrast legibility against the dark dial plate. The outer track features fine minute demarcations that ensure an uncluttered, balanced presentation. Framing the dial is a fixed, mirror-polished solid stainless steel bezel that flows smoothly into the case contours. Beneath its tailored exterior, the watch is driven by Seiko’s proven in-house Calibre 4R38 Japanese automatic mechanical movement, engineered and manufactured at Seiko’s dedicated horological facilities in Japan. Operating at a steady frequency of 21,600 vibrations per hour (3 Hz), this 24-jewel self-winding caliber harnesses the natural kinetic energy of the wearer’s wrist to wind the mainspring, delivering approximately 41 hours of autonomous power reserve on a full wind. Designed purposefully without a calendar mechanism to preserve dial symmetry and the purity of the open-heart layout, the caliber features both automatic self-winding and manual hand-winding capabilities, along with a hacking seconds (stop-seconds) mechanism that halts the seconds hand when the crown is pulled out for down-to-the-second time synchronization. Built with Seiko’s proprietary Diashock shock-absorbing architecture, the movement delivers dependable stability rated to a factory precision tolerance of +45 to -35 seconds per day and incorporates JIS Class 1 magnetic resistance (4,800 A\/m), protecting timekeeping accuracy against daily electromagnetic exposure from smartphones and laptops. The case is engineered with classic, feminine dress proportions, measuring an official 33.7mm in case diameter with a slender case profile thickness of 10.8mm, a compact 39.8mm lug-to-lug distance, and a standard 16mm lug width, delivering an ergonomic, featherlight drape on slender wrists. The solid 316L stainless steel case architecture combines vertical hairline satin brushing across the upper lugs with mirror-polished case flanks and bevels to create a sharp, multi-dimensional presence. Dial protection is provided by a high-grade flat Hardlex crystal engineered to withstand everyday impacts and surface abrasions. Built for dependable everyday resilience, the watch features an ergonomic fluted pull-out crown at 3 o'clock and an exhibition see-through screw-down caseback that allows the wearer to view the mechanical balance and oscillating rotor, while securing an impressive 10-bar (100 meters \/ 330 ft) water resistance rating, making it fully resilient against heavy rain, accidental splashes, and swimming. The timepiece comes completed on an integrated solid stainless steel multi-link construction featuring satin-brushed outer rows and polished center link accents, secured by a sturdy one-push three-fold deployment clasp with an easy-adjustment sizing system.\u003c\/p\u003e","brand":"MonaWatch","offers":[{"title":"Default Title","offer_id":67704802312506,"sku":"HFB007J","price":1160.0,"currency_code":"AED","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0920\/5858\/3354\/files\/NewProject_b748a52c-7ccf-44a9-b345-f163656c40c6.webp?v=1792049767","url":"https:\/\/www.monawatch.com\/products\/seiko-selection-open-heart-hfb007j-womens-watch","provider":"MonaWatch","version":"1.0","type":"link"}