The Longines Master Collection L2.910.4.78.6 is a 40mm stainless steel watch featuring a silver 'barleycorn' dial with painted Arabic numerals and blued steel hands. It is powered by the self-winding mechanical movement Caliber L897, operating at 25,200 vibrations per hour and offering a power reserve of approximately 64 hours. The watch includes an annual calendar function displaying the month and date at the 3 o'clock position. Protected by a scratch-resistant sapphire crystal, it has a transparent case back and is water-resistant up to 3 bar (30 meters). The stainless steel bracelet is secured with a triple safety folding clasp and push-piece opening mechanism. Reference number: L2.910.4.78.6.