It is 18K gold. It is 35.5 mm in diameter. Very good (Worn with little to no signs of wear) It has a box, no certificates and documents. The Longines Flagship Heritage is a watch that looks as if it came straight from the 1950’s. It has a subtly sized case fitted with a hesalite crystal. The dial features elegant stick markers and time is indicated through hands in dauphine style. Powering this watch is the automatic caliber L609. This watch features a automatic movement beating at a frequency of 28800 bph ( 4 Hz) to provide a 42-hour power reserve when fully wound. The yellow gold case measures 35.5 mm in diameter and roughly mm thick, with 17mm lug width. The round case is paired with a white color dial with dauphine-shaped hands, and a stick / dot hour markers and minute track, covered by a mineral glass. Longines’s Heritage model L4.746.6 water resistant up to 30 meters (98 ft).