The Jaeger-LeCoultre Master Control Chronometre Perpetual Calendar is a perpetual calendar on an integrated bracelet. The steel reference Q4178180 has a 39 mm case that is 9.2 mm thick, with alternating polished and brushed surfaces, a sapphire case back and water resistance to 5 bar. Its blue-grey gradient sunray dial carries polished rhodium-finished numerals and hour markers, Dauphine hands and four recessed sub-dials with an opaline outer ring and azuré centre. Inside is the in-house automatic Calibre 868, which is 4.72 mm thick and 28 mm wide, with 332 components, 46 jewels, a 4 Hz (28,800 vph) frequency and a 70-hour power reserve. It is COSC-certified and also carries the brand’s High Precision Guarantee (HPG) seal, which tests the cased watch over three days of simulated wear.

The month and leap year sit at 12 o’clock, the day at 3, the moon phase at 6 and the date at 9. Jaeger-LeCoultre states the calendar will need no correction until 2100 if the watch keeps running, and a single corrector on the case side adjusts all indications. The three-row bracelet was designed for the new Master Control Chronometre line, with V-shaped bevels that echo the Dauphine hands and a clasp with winter and summer adjustment. The watch launched at Watches and Wonders 2026 with Date and Date Power Reserve models. A pink gold version, Q417216J, has a bronze-toned dial. Prices are USD 45,700 or EUR 39,500 in steel, and EUR 72,500 in pink gold, which Jaeger-LeCoultre US lists as price on request.

Launch coverage was positive. Fratello named the Master Control Chronometre line one of the most surprising releases of the first half of 2026. Its writer said he usually finds perpetual calendar dials too crowded, but felt Jaeger-LeCoultre had got this one right, and praised the slim cases, finishing and bracelet. Wristreview called the Perpetual Calendar the sleeper hit of the brand’s 2026 releases and one of the slimmer, more wearable complicated watches of the year. Watchonista highlighted the single corrector as making ownership less intimidating. The main reservation in early coverage was that the line enters a crowded segment of integrated-bracelet sports watches. As of October 2026 the watch is a current catalogue model, sold through boutiques and retailers, so it is in production.