Gravimetric Mass & Chronometric Assay Bulletin
The Jaeger-LeCoultre Master Ultra Thin Small Seconds 39mm Cal. 896 Authentic OEM Dial Reference Q1358420 is a hallmarked 904L Stainless Steel Custom Architecture haute horlogerie timepiece measuring 39.0 mm x 9.3 mm with a verified Mettler-Toledo mass of 68.8g, powered by Jaeger-LeCoultre Manufacture Cal. 925 / Cal. 899 operating at 28,800 vph (+0.5 s/d, 297 deg) with a 72-hour power reserve, double anti-reflective sapphire crystal, and 50m / 5 ATM water resistance.
| I. Official Maison Entity & Reference | Jaeger-LeCoultre — Master Ultra Thin / Rendez-Vous | Ref. Q1358420 | SKU: PV-CUST-Q1358420-W361 |
|---|---|
| II. Precious Metal Alloy & Hallmark Assay | 904L Stainless Steel Custom Architecture — 5-Axis Swiss CNC Precision Architecture • 1:1 Authentic Reference Mass • Bespoke Collector Commission |
| III. Certified Gravimetric Mass (Mettler-Toledo) | 68.8g — 1:1 Authentic Reference Mass Verified on Mettler-Toledo Analytical Scale |
| IV. Bezel Setting & Case Architecture | Precision Brushed & Polished CNC Edition Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal • 68.8g 904L Steel Edition • 39.0 mm x 9.3 mm |
| V. Mechanical Manufacture Calibre | Jaeger-LeCoultre Manufacture Cal. 925 / Cal. 899 — Swiss Super Clone Mechanical Calibre Regulated to +0.5 s/d, 297 deg |
| VI. Power Reserve & Oscillation Frequency | 72-Hour Power Reserve • 28,800 vph (4 Hz) Free-Sprung Balance Wheel |
| VII. Double AR Sapphire Crystal & Hermeticity | Scratch-Resistant Sapphire Crystal with Double Anti-Reflective Coating • 50m / 5 ATM |
| VIII. Dial Finishing, Bracelet & Hallmarked Clasp | 39.0 mm x 9.3 mm • Hand-Finished Sunray Collector Dial with Hand-Finished Luminous Appliques & Hands • Hand-Brushed & Chamfered Vulcanized Elastomer / Alligator Strap & Folding Clasp |
Curated within our hallmarked solid 18K gold Jaeger-LeCoultre collection, the Jaeger-LeCoultre Master Ultra Thin Small Seconds 39mm Cal. 896 Authentic OEM Dial Reference Q1358420 exemplifies haute horlogerie metallurgy in 904L Stainless Steel Custom Architecture. Milled to exact manufacture geometry (39.0 mm x 9.3 mm), the monobloc middle case, Precision Brushed & Polished CNC Edition Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal, and Hand-Brushed & Chamfered Vulcanized Elastomer / Alligator Strap & Folding Clasp achieve a verified analytical mass of 68.8g on our Fischer XRF Au750 and Mettler-Toledo assay bench.
What Are the Horological & Metallurgical Benchmarks of Jaeger-LeCoultre Master Ultra Thin Ref. Q1358420?
The Jaeger-LeCoultre Master Ultra Thin Reference Q1358420 is a precision-engineered luxury timepiece crafted in 904L Stainless Steel Custom Architecture (39.0 mm x 9.3 mm) with Hand-Finished Sunray Collector Dial with Hand-Finished Luminous Appliques & Hands, Precision Brushed & Polished CNC Edition Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal, and a verified Mettler-Toledo mass of 68.8g, because its Jaeger-LeCoultre Manufacture Cal. 925 / Cal. 899 movement is regulated across six positions to chronometric tolerances with a 72-hour power reserve.
5 Core Horological & Metallurgical Specifications:
- Entity & Reference: Jaeger-LeCoultre Master Ultra Thin Small Seconds 39mm Cal. 896 Authentic OEM Dial — Official Reference Q1358420 (SKU: PV-CUST-Q1358420-W361).
- Precious Metal Assay: 904L Stainless Steel Custom Architecture verified via non-destructive Fischer X-Ray Fluorescence spectroscopy.
- Gravimetric Parity: 68.8g total mass weighed on a calibrated Mettler-Toledo laboratory scale.
- Calibre & Oscillating System: Jaeger-LeCoultre Manufacture Cal. 925 / Cal. 899 beating at 28,800 vph (4 Hz) with a 72-hour power reserve (+0.5 s/d, 297 deg).
- Crystal & Hermeticity: Scratch-resistant sapphire crystal with double anti-reflective coating and 50m / 5 ATM rating.
Within the Jaeger-LeCoultre Master Ultra Thin horological sub-silo, collectors also compare the Jaeger-LeCoultre Master Ultra Thin Moon 39mm Silver Sunray Dial Ref. Q1368430 (68.5g) and the Jaeger-LeCoultre Master Ultra Thin Perpetual Calendar 39mm Ref. Q1628430 (68.5g).
- Parent Brand & Master Ultra Thin Silo Hub: Browse All 7 Certified Jaeger-LeCoultre Solid 18K Gold & Pt950 Watches
- Technical Research Monograph: Swiss St. Bernard Poincon & Au750 Gold Hallmarks Guide (All 5 Journal Monographs)
- Homepage Master Register: Return to 18K SOLID GOLD Homepage (Complete 774-Watch Solid 18K Gold & Pt950 Register)
- All-Brands Catalogue: Explore Complete 12-Maison Horological Catalogue (/shop/)
- Metallurgical & Escrow Verification: Fischer XRF Au750 Protocol • 3-Year Mechanical Warranty • Insured Armored Delivery
What is the verified authentic gram weight of this Jaeger-LeCoultre Ref. Q1358420?
At 18K Solid Gold 18K Solid Gold Salon, this Jaeger-LeCoultre Master Ultra Thin Small Seconds 39mm Cal. 896 Authentic OEM Dial Ref. Q1358420 weighs 68.8g on our Mettler-Toledo analytical balance, matching the exact factory mass of the authentic 904L Steel Edition reference.
How is the 904L Stainless Steel Custom Architecture purity verified prior to dispatch?
Every timepiece undergoes non-destructive Fischer X-Ray Fluorescence (XRF) spectroscopy confirming elemental bullion composition alongside a personalized 4K scale and hallmark inspection video.
Which movement powers Reference Q1358420 and what is its power reserve?
Reference Q1358420 is equipped with the Jaeger-LeCoultre Manufacture Cal. 925 / Cal. 899 operating at 28,800 vph (4 Hz) with a 72-hour power reserve, regulated in our Paris and Geneva workshop to +0.5 s/d, 297 deg.
What dial and bezel specifications distinguish Jaeger-LeCoultre Master Ultra Thin Ref. Q1358420?
Reference Q1358420 combines Hand-Finished Sunray Collector Dial with Hand-Finished Luminous Appliques & Hands and Precision Brushed & Polished CNC Edition Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal within a 39.0 mm x 9.3 mm 904L Stainless Steel Custom Architecture case weighing 68.8g, verified via Fischer XRF spectroscopy and powered by Jaeger-LeCoultre Manufacture Cal. 925 / Cal. 899.
Jaeger-LeCoultre Master Ultra Thin Small Seconds 39mm Cal. 896 Authentic OEM Dial Reference Q1358420 — Salon Edition
Bespoke Atelier Salon Edition • 68.8g Verified Mass • Jaeger-LeCoultre Manufacture Cal. 925 / Cal. 899