IMPORTANT: The dial shows a small damage between the 5 and 6 o’clock indexes, which is not particularly visible due to the high rounded crystal that slightly distorts the area. OFFERED SERVICES & PROFESSIONAL GUARANTEES: 1. PREMIUM SHIPPING via DHL EXPRESS BUSINESS (Priority commercial account) 2. FAST DELIVERY in 1–3 BUSINESS DAYS (U.S./Europe) 3. 100% FULLY INSURED PACKAGE during transit 4. SECURE HANDOVER with Safety Signature Request 5. TAX COMPLIANCE: HST/GST included for shipments within Canada 6. EXTENSIVE TESTING: Monitored & tested for accuracy over weeks prior to listing 7.REGULATED FOR ECCELLENT TIMEKEEPING 8. DEALER INVOICE: Official commercial invoice provided with the purchase 9. BUYER PROTECTION: Safe payment via Chrono24 Trusted Escrow Checkout 10. 14-DAY RETURN POLICY: Guaranteed return policy (must be returned unaltered) --- Gruen Precision (ROLEX Partner 1920s/1930s) Cal.N 510 SS - Aka "Ocean Chief" Variant — 3rd GENERATION 1960s — OVERSIZE JUMBO Case 37.5mm/38mm including Bezel / 41mm including Crown — MADE SWITZERLAND Description: For your consideration, an exceptional and rare Gruen Precision 510 SS "Skin Diver" from the early 1960s. This model is widely recognized by collectors as the Aka "Ocean Chief" Variant due to its iconic "Explorer-style" dial with triangular luminous markers, identical to its famous sibling. Key Highlights: Oversize Case: Rare 37.5mm (38mm including Bezel) stainless steel case (40mm including crown), offering a much stronger wrist presence than the standard 34-36mm versions. Movement: Powered by the legendary Gruen Cal. N510SS manual wind movement—the same caliber series worn by James Bond in Dr. No. Condition: Excellent 9/10 aesthetic condition Case. The case retains sharp lines, and the dial features a stunning, original warm patina. Performance: Professionally timed. It is currently running exceptionally well at +1-5 seconds per day. Technical Specs: ANTI-MAGNETIC SHIELD: Includes the original internal metal dust cover (soft iron shield), ensuring protection for the movement and preserving its historical integrity. REFERENCE: N 510 SS (Movement). CRYSTAL: High-domed original-style plexiglass. STRAP: New Vintage-style brown leather. A perfect opportunity to own a piece of Gruen diving history in collector-grade condition. This "Ocean Chief" aesthetic variant offers the perfect blend of tool-watch ruggedness and slim, manual-wind elegance.