The Longines Ultra-Chron Diver L2.836.4.52.9 was introduced in 2022. Based on the original Ultra-Chron Diver of 1968, this watch features a cushion-shaped case of 43.00mm, water resistant up to 300 meters. Modern upgrades include the self-winding, high-frequency caliber L836.6 within (certified 'Ultra Chronometer' by TimeLab) and the sapphire crystal bezel insert.