The Jaeger-LeCoultre Duomètre Chronographe Q6012521 features a 42mm 18K rose gold round case with concave/curved lugs and 13.6mm thickness. Silver or skeletonized dial with sub-dial for hours/minutes at 10 o'clock, small seconds, 50-hour power reserve indicator for main movement (at 7-8 o'clock), chronograph 60-minute/12-hour sub-dial at 2 o'clock, and chronograph power reserve at 4-5 o'clock. Powered by manual-winding Caliber 380 with the revolutionary Duomètre system featuring dual independent power trains (one for time, one for chronograph) linked to a single balance beating at 3Hz (21,600 vph). Mono-pusher chronograph (start/stop/reset) meeting chronometer-grade ISO 3159 standards. Movement has 40 jewels. Scratch-resistant sapphire crystal and transparent sapphire caseback. Brown alligator leather strap with 18K rose gold tang buckle.