The Longines Ultra-Chron Classic is a high-frequency automatic watch in stainless steel, made in 40 mm and 37 mm sizes. The 40 mm reference L2.937.4.72.6 has a lug-to-lug length of 47.2 mm and 21 mm lugs. The 37 mm version measures 44.6 mm lug to lug with 19 mm lugs. Both cases are 10.95 mm thick including the box-shaped sapphire crystal, which has several layers of anti-reflective coating on both sides. They have a screwed solid case back with the Ultra-Chron logo and water resistance to 5 bar (50 m). The domed silver sunray dial has a central crosshair, faceted applied markers and hands filled with black lacquer, and a trapezoidal date window at 3 o’clock. There is no lume. Inside is the Longines-exclusive calibre L836.6, made by ETA, with 25 jewels and a silicon balance spring. It beats at 36,000 vph (5 Hz) and has a power reserve of up to 52 hours. Each watch is chronometer-certified by TIMELAB in Geneva.

The design closely follows the first Ultra-Chron, ref. 7827 from 1967, a 35 mm watch with the high-frequency calibre 431. The 1968 Ultra-Chron Diver followed, and its 2022 reissue introduced the L836.6. The Classic was launched in October 2025 in four references: L2.937.4.72.6 (40 mm, bracelet), L2.937.4.72.2 (40 mm, black alligator strap), L2.537.4.72.6 (37 mm, bracelet) and L2.537.4.72.2 (37 mm, strap). The new five-row bracelet has a channel down the centre links and a double-security folding clasp with toolless micro-adjustment. Time and Watches gave European prices of EUR 3,950 on the bracelet and EUR 3,800 on the strap. Longines US lists the 40 mm bracelet model at USD 4,000.

The press mostly welcomed the reissue for its faithful design and high-beat movement. Fratello’s hands-on called it a great release that feels almost like a new-old-stock 1967 Ultra-Chron and praised the well-proportioned dials in both sizes and the new bracelet. Some Fratello readers felt the date window sits too far from the edge on the 40 mm dial. Monochrome described the design as a 95% accurate copy of the original. It called the silver dial almost too classic, noted the lack of lume and found 50 m water resistance sufficient but unexceptional. As of October 2026 the Ultra-Chron Classic is part of Longines’ permanent collection and in production.