{"reference": {"slug": "hublot-521", "brand": "Hublot", "ref": "521", "model": "Classic Fusion Chronograph", "case_material": "Titanium", "provenance": "extracted_from_auction_comps", "url": "https://mostexpensivewatches.net/reference/hublot-521", "description": "The Hublot Classic Fusion Chronograph 521.NX.1171.RX is a core component of the brand’s contemporary catalog, having remained in steady production since the early 2010s. Collectors evaluate this reference based on its 45mm Grade 5 titanium case, which offers a high strength-to-weight ratio and a more muted aesthetic compared to the brand's Big Bang series. It utilizes the HUB1143 caliber, an automatic movement based on the ETA 2892-A2 with a Dubois-Dépraz chronograph module, providing a 42-hour power reserve. The dial features a symmetrical bi-compax layout with a date window at six o'clock. On the secondary market, this reference typically trades between $6,000 and $8,500 depending on condition and inclusion of original documentation. A notable production variant is the \"Racing Grey\" edition, which replaces the standard matte black dial with a sunray-finished grey surface, often commanding a slight premium."}, "listing_stats": {"count": 1, "median": 8350.0, "low": 8350.0, "high": 8350.0, "brands": 1, "merchants": 1}, "listings": [{"id": "h_6960396632139", "title": "Hublot Hublot Classic Fusion Aerofusion Chronograph 525.NX.0170.LR", "brand": "Hublot", "model": "Hublot Classic Fusion Aerofusion Chronograph 525.NX.0170.LR", "reference": "0170.", "price_usd": 8350.0, "currency": "USD", "condition": "excellent", "box_papers": "full_set", "year": null, "case_material": "Stainless Steel", "case_size_mm": 40.0, "movement": "Automatic", "complications": ["Chronograph"], "merchant_slug": "hodinkee", "merchant_name": "Hodinkee Shop", "image_url": "https://cdn.shopify.com/s/files/1/0146/0732/products/Hublot-Classic-Fusion-Aerofusion-525-NX-0170-LR-10-10-HUB-N164YL-034bdb9e101a.jpg?v=1710463894", "detail_url": "https://mostexpensivewatches.net/listing/h_6960396632139", "buy_url": "https://mostexpensivewatches.net/out/h_6960396632139", "available": false}], "auction_lots": [{"slug": "hublot-521-nx-7170-rx-0121-2023", "brand": "Hublot", "reference": "521.NX.7170.RX.0121", "model": "Classic Fusion Chronograph", "case_material": "Titanium", "hammer_usd": 9828, "year_sold": 2023, "venue": "Christie's Hong Kong", "lot_summary": "A 45mm titanium automatic chronograph featuring a blue dial and a matching blue rubber and crocodile strap.", "source_url": "https://www.christies.com/en/lot/lot-6441070", "provenance": "ai_generated_grounded", "url": "https://mostexpensivewatches.net/auctions/hublot-521-nx-7170-rx-0121-2023"}]}